Draft California 2026 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 7 - Colorado River Basin Region

Water Body Name:	Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
Water Body ID:	CAR7132000020080709122810
Water Body Type:	River & Stream

DECISION ID	77981	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Toxicity
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under section 3.6 of the Listing Policy. Under section 3.6 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Four of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Four of six water samples exhibit toxicity when compared to control samples and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 77981, Toxicity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	31972
Pollutant:	Toxicity
LOE Subgroup:	Toxicity
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	3
Data and Information Type:	TOXICITY TESTING
Data Used to Assess Water Quality:	Five samples were collected to evaluate water toxicity. Three of the samples exhibited significant toxicity to Ceriodaphnia dubia reproduction. The toxicity test included survival and reproduction of Ceriodaphnia dubia and survial and biomass of Pimephales promelas. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location with the same lab sample id (if provided).
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. Region 7 Basin Plan.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. For SWAMP data exceedances are counted with the significant effect code SL. SL is defined as the result being significant compared to the negative control based on a statistical test, less than stated the alpha level, AND less than the evaluation threshold.
Guideline Reference:	Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013
Spatial Representation:	The samples were collected at station 713CRNVBD.
Temporal Representation:	The samples were collected in October and April 2008, October 2005 and May 2007.
Environmental Conditions:
QAPP Information:	Data quality is good. Data results were recorded in the SWAMP database and follwed SWAMP protocols.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 77981, Toxicity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	125402
Pollutant:	Toxicity
LOE Subgroup:	Toxicity
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	1
Data and Information Type:	TOXICITY TESTING
Data Used to Assess Water Quality:	1 of the 1 samples collected by SWAMP RWB7 Monitoring for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Ceriodaphnia dubia, for Survival, Ceriodaphnia dubia, for Young/female
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Colorado River Basin Plan)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 stations. Monitoring site(s): ( 713CRNVBD )
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04.
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 77981, Toxicity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32173
Pollutant:	Toxicity
LOE Subgroup:	Toxicity
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	3
Data and Information Type:	TOXICITY TESTING
Data Used to Assess Water Quality:	Five samples were collected to evaluate water toxicity. Three of the samples exhibited significant toxicity to Ceriodaphnia dubia reproduction. The toxicity test included survival and reproduction of Ceriodaphnia dubia and survial and biomass of Pimephales promelas. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location with the same lab sample id (if provided).
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. Region 4 Basin Plan.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. For SWAMP data exceedances are counted with the significant effect code SL. SL is defined as the result being significant compared to the negative control based on a statistical test, less than stated the alpha level, AND less than the evaluation threshold.
Guideline Reference:	Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013
Spatial Representation:	The samples were collected at station 713CRNVBD.
Temporal Representation:	The samples were collected in October and April 2008, October 2005 and May 2007.
Environmental Conditions:
QAPP Information:	Data quality is good. Data results were recorded in the SWAMP database and follwed SWAMP protocols.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 77981, Toxicity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	125388
Pollutant:	Toxicity
LOE Subgroup:	Toxicity
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	1
Data and Information Type:	TOXICITY TESTING
Data Used to Assess Water Quality:	1 of the 1 samples collected by SWAMP RWB7 Monitoring for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day, at the same location with the same lab sample ID (if provided). The following organisms and parameters were utilized for the toxicity tests: Ceriodaphnia dubia, for Survival, Ceriodaphnia dubia, for Young/female
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Colorado River Basin Plan)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 stations. Monitoring site(s): ( 713CRNVBD )
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04.
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156482	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1, 1-dichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156482, 1, 1-dichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321290
Pollutant:	1, 1-dichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156482, 1, 1-dichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34758
Pollutant:	1, 1-dichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1-Dichloroethane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for 1, 1-Dichloroethane is 5 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156477	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,1,1,2-Tetrachloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156477, 1,1,1,2-Tetrachloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320482
Pollutant:	1,1,1,2-Tetrachloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156479	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,1,1-Trichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156479, 1,1,1-Trichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321291
Pollutant:	1,1,1-Trichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156479, 1,1,1-Trichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34723
Pollutant:	1,1,1-Trichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1, 1-Trichloroethane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for 1, 1, 1-Trichloroethane is 200 ug/L (Title 22 of the California Code of Regulations ).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156486	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,1,2,2-Tetrachloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156486, 1,1,2,2-Tetrachloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319818
Pollutant:	1,1,2,2-Tetrachloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location on this segment of the Colorado River. One water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segement of the river. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Benzene, 0.0005 mg/l Carbon Tetrachloride, 0.0005 mg/l 1,2-Dichloroethane, and 0.001 mg/l 1,1,2,2-Tetrachloroethane (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156486, 1,1,2,2-Tetrachloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35669
Pollutant:	1,1,2,2-Tetrachloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Two samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 1, 1, 2, 2-Tetrachloroethane criteria for the protection of human health from the consumption of water and organisms is 0.17 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156556	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,1,2-Trichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156556, 1,1,2-Trichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34756
Pollutant:	1,1,2-Trichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 1, 2-Trichloroethane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 1, 1, 2-Trichloroethane criteria for the protection of human health from the consumption of water and organisms is 0.60 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156556, 1,1,2-Trichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320256
Pollutant:	1,1,2-Trichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156556, 1,1,2-Trichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321300
Pollutant:	1,1,2-Trichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156380	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156380, 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321301
Pollutant:	1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156380, 1,1-Dichloroethylene (DCE)/ Vinylidene Chloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34779
Pollutant:	1,1-Dichloroethylene (DCE)/ Vinylidene Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Two samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 1, 1-Dichloroethylene criteria for the protection of human health from the consumption of water and organisms is 0.057ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156500	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,1-Dichloropropene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156500, 1,1-Dichloropropene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320483
Pollutant:	1,1-Dichloropropene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156548	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2,3-Trichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156548, 1,2,3-Trichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320041
Pollutant:	1,2,3-Trichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Methyl Chloride, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, or 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156497	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2,3-Trichloropropane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156497, 1,2,3-Trichloropropane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320484
Pollutant:	1,2,3-Trichloropropane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156388	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2,4-Trichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156388, 1,2,4-Trichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321310
Pollutant:	1,2,4-Trichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156388, 1,2,4-Trichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34812
Pollutant:	1,2,4-Trichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2, 4-Trichlorobenzene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for 1,2,4-Trichlorobenzene is 5 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156392	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2,4-Trimethylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156392, 1,2,4-Trimethylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320313
Pollutant:	1,2,4-Trimethylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156399	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2-Dibromo-3-chloropropane (DBCP)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156399, 1,2-Dibromo-3-chloropropane (DBCP) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320495
Pollutant:	1,2-Dibromo-3-chloropropane (DBCP)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156402	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2-Dichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156402, 1,2-Dichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319830
Pollutant:	1,2-Dichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location on this segment of the Colorado River. One water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segement of the river. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Benzene, 0.0005 mg/l Carbon Tetrachloride, 0.0005 mg/l 1,2-Dichloroethane, and 0.001 mg/l 1,1,2,2-Tetrachloroethane (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156402, 1,2-Dichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320257
Pollutant:	1,2-Dichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156402, 1,2-Dichloroethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34782
Pollutant:	1,2-Dichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-Dichloroethane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 1, 2-Dichloroethane criterion for the protection of human health from the consumption of water and organisms is 0.38 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156470	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2-Dichloroethylene,-trans
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156470, 1,2-Dichloroethylene,-trans Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321311
Pollutant:	1,2-Dichloroethylene,-trans
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156470, 1,2-Dichloroethylene,-trans Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34734
Pollutant:	1,2-Dichloroethylene,-trans
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-trans-dichlorethylene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for trans-1, 2-Dichloroethene is 10 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156407	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,2-Dichloropropane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156407, 1,2-Dichloropropane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320258
Pollutant:	1,2-Dichloropropane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156407, 1,2-Dichloropropane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321320
Pollutant:	1,2-Dichloropropane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156407, 1,2-Dichloropropane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34802
Pollutant:	1,2-Dichloropropane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-Dichloropropane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 1, 2-Dichloropropane criteria for the protection of human health from the consumption of water and organisms is 0.52 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156489	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,3,5-Trimethylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156489, 1,3,5-Trimethylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320453
Pollutant:	1,3,5-Trimethylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156498	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1,3-Dichloropropane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156498, 1,3-Dichloropropane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320496
Pollutant:	1,3-Dichloropropane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156521	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1-Methylnaphthalene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156521, 1-Methylnaphthalene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319556
Pollutant:	1-Methylnaphthalene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of 1-Methylnaphthalene, 2,3,5-Trimethylnaphthalene, or 2,6-Dimethylnaphthalene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156520	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1-Methylphenanthrene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156520, 1-Methylphenanthrene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319156
Pollutant:	1-Methylphenanthrene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Phenanthrene, or 1-Methylphenanthrene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156499	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	2,2-Dichloropropane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156499, 2,2-Dichloropropane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320497
Pollutant:	2,2-Dichloropropane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156522	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	2,3,5-Trimethylnaphthalene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156522, 2,3,5-Trimethylnaphthalene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319557
Pollutant:	2,3,5-Trimethylnaphthalene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of 1-Methylnaphthalene, 2,3,5-Trimethylnaphthalene, or 2,6-Dimethylnaphthalene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156523	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	2,6-Dimethylnaphthalene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156523, 2,6-Dimethylnaphthalene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319570
Pollutant:	2,6-Dimethylnaphthalene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of 1-Methylnaphthalene, 2,3,5-Trimethylnaphthalene, or 2,6-Dimethylnaphthalene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156495	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	2-Chlorotoluene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156495, 2-Chlorotoluene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319539
Pollutant:	2-Chlorotoluene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of 2-Chlorotoluene, 4-Chlorotoluene, or p-Cymene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156550	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	2-Hexanone
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156550, 2-Hexanone Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319750
Pollutant:	2-Hexanone
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, or 2-Hexanone for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156463	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	2-Methylnaphthalene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156463, 2-Methylnaphthalene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319571
Pollutant:	2-Methylnaphthalene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Naphthalene, 2-Methynaphthalene, or Acenaphthylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156496	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	4-Chlorotoluene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156496, 4-Chlorotoluene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319554
Pollutant:	4-Chlorotoluene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of 2-Chlorotoluene, 4-Chlorotoluene, or p-Cymene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156480	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Acenaphthene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156480, Acenaphthene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321027
Pollutant:	Acenaphthene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156481	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Acenaphthylene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156481, Acenaphthylene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319572
Pollutant:	Acenaphthylene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Naphthalene, 2-Methynaphthalene, or Acenaphthylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156549	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Acetone
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156549, Acetone Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319762
Pollutant:	Acetone
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, or 2-Hexanone for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156510	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Aldrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128910
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Aldrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Aldrin criteria for the protection of human health from the consumption of water and organisms is 0.00013 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45923
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Aldrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127852
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Aldrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The aldrin criterion maximum concentration to protect aquatic life in freshwater is 3 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34808
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Aldrin.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The aldrin criterion maximum concentration to protect aquatic life in freshwater is 3 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45924
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Aldrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128616
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Aldrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Aldrin criterion maximum concentration to protect aquatic life in freshwater is 3 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34824
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Aldrin.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Aldrin criterion maximum concentration to protect aquatic life in freshwater is 3 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320239
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156510, Aldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34820
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Aldrin criteria for the protection of human health from the consumption of water and organisms is 0.00013 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	159278	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Alkalinity as CaCO3
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 159278, Alkalinity as CaCO3 Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127372
Pollutant:	Alkalinity as CaCO3
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Alkalinity as CaCO3.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The Alkalinity as CaCO3 criteria for the protection of freshwater aquatic life is 20000 ug/L (National Recommended Water Quality Criteria, 2009).
Guideline Reference:	2012 Edition of the Drinking Water Standards and Health Advisories
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159278, Alkalinity as CaCO3 Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	334440
Pollutant:	Alkalinity as CaCO3
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Alkalinity as CaCO3.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2020-10-26 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159278, Alkalinity as CaCO3 Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	334441
Pollutant:	Alkalinity as CaCO3
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Alkalinity as CaCO3.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The USEPA recommended alkalinity criterion continuous concentration (CCC) for the protection of aquatic life in freshwater is a minimum value of 20,000 ug/L (4-day average).
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2020-10-26 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156558	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Aluminum
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 156558, Aluminum Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128191
Pollutant:	Aluminum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Aluminum.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Secondary MCL for aluminum is 0.2 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156558, Aluminum Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321321
Pollutant:	Aluminum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156558, Aluminum Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320071
Pollutant:	Aluminum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156558, Aluminum Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35177
Pollutant:	Aluminum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Aluminum.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for aluminum is 0.2 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156542	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Ametryn
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156542, Ametryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319344
Pollutant:	Ametryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ametryn, Prometryn, Simetryn, or Terbutryn for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156542, Ametryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128470
Pollutant:	Ametryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ametryn.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA Health Advisory for lifetime exposure to Ametryn as a drinking water level is a concentration of 0.06 mg/L
Guideline Reference:	2012 Edition of the Drinking Water Standards and Health Advisories
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	103042	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Ammonia
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Seven lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the samples exceed the water quality objectives. Sample sizes for each matrix/fraction/beneficial use/objective combination were less than 16. The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 103042, Ammonia Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127030
Pollutant:	Nitrogen, ammonia (Total Ammonia)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference:	Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 103042, Ammonia Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127052
Pollutant:	Nitrogen, ammonia (Total Ammonia)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as \the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure.\""
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 103042, Ammonia Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34570
Pollutant:	Nitrogen, ammonia (Total Ammonia)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceed the water USEPA Temperature and pH-Dependent values of the CCC (Chronic Criterion) for Fish Early Life Stages Present for ammonia. 3 of the 6 data samples are reported as Non-Detect (ND). These 3 ND values are less than or equal to the water quality standard, the value will be considered as meeting the water quality standard, objective, criterion, or evaluation guideline.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Water Quality Control Plan, Colorado River Basin Region (RWQCB 2006): All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. There is no water quality objective for ammonia in the Water Quality Control Plan, Colorado River Basin. Instead, the USEPA criteria for ammonia was used as Temperature and pH-Dependent Values of the CCC (Chronic Criterion)for Fish Early Life Stages Present.
Objective/Criterion Reference:	1999 Update of Ambient Water Quality Criteria for Ammonia
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Sample was collected at 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 103042, Ammonia Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127041
Pollutant:	Nitrogen, ammonia (Total Ammonia)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference:	Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 103042, Ammonia Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127063
Pollutant:	Nitrogen, ammonia (Total Ammonia)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference:	Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2013-11-05 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 103042, Ammonia Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128507
Pollutant:	Nitrogen, ammonia (Total Ammonia)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	EPA's Lifetime Health advisory level for total ammonia is 30.0 mg/L as stated on page 8 of the 2006 edition of the drinking water standards and health advisories. This Advisory Level is defined as \the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for up to ten days of exposure.\""
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2013-11-05 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 103042, Ammonia Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128518
Pollutant:	Nitrogen, ammonia (Total Ammonia)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.
Objective/Criterion Reference:	Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2013-11-05 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156377	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Anthracene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156377, Anthracene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321028
Pollutant:	Anthracene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156378	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Arsenic
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320240
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333467
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Arsenic .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for arsenic is the probable effect concentration (PEC) of 33 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333466
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Arsenic .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for arsenic is the probable effect concentration (PEC) of 33 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35179
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Arsenic.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 0.150 mg/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321330
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127067
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Arsenic.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35222
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Arsenic.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 0.150 mg/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127068
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Arsenic.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45925
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Arsenic. One composite (6 fish per composite) was generated from one species: largemouth bass. One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for arsenic in fish tissue is 0.0034 ppm. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. It is assumed that 10% of the total arsenic is present as inorganic arsenic. This constituent is a carcinogen therefore the risk level is set to one in a million.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319081
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the USFWS Biological Effect Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	United State Fish and Wildlife Service (USFWS) Biological Effect Criteria for the protection of aquatic life uses were used for the following constituents: 0.25 mg/l Arsenic, and 15 mg/l Copper (USFWS, 1998).
Guideline Reference:	Guidelines for Interpretation of the Biological Effect of Selected Constituents in Biota, Water, and Sediment. US Department of Interior report.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35180
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Arsenic.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for arsenic is 0.01 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156378, Arsenic Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127069
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Arsenic.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 150 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156379	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Atrazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156379, Atrazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351615
Pollutant:	Atrazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Atrazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of < 1 ug/L for a nonvascular plant (acute). The benchmark was derived from a 'less-than' value (for example, <1,500) and may underestimate toxicity.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156379, Atrazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351616
Pollutant:	Atrazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Atrazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of < 1 ug/L for a nonvascular plant (acute). The benchmark was derived from a 'less-than' value (for example, <1,500) and may underestimate toxicity.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156379, Atrazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319072
Pollutant:	Atrazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Six water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Atrazine, and 0.004 mg/l Simazine (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Six water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October. No sample was collected in October 2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156379, Atrazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35244
Pollutant:	Atrazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Atrazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Atrazine is 1 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156379, Atrazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127267
Pollutant:	Atrazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Atrazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of < 1 ug/L for a nonvascular plant (acute). The benchmark was derived from a \less-than\" value (for example, <1,500) and may underestimate toxicity."
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156379, Atrazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127265
Pollutant:	Atrazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Atrazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of < 1 ug/L for a nonvascular plant (acute). The benchmark was derived from a \less-than\" value (for example, <1,500) and may underestimate toxicity."
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156379, Atrazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127268
Pollutant:	Atrazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Atrazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Atrazine is 0.001 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156545	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Atroton
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156545, Atroton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319347
Pollutant:	Atroton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Atroton, Prometon, or Secbumeton for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156535	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Azinphos, Ethyl (Ethyl Guthion)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156535, Azinphos, Ethyl (Ethyl Guthion) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319114
Pollutant:	Azinphos, Ethyl (Ethyl Guthion)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Azinphos, methyl, or Azinphos, ethyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156422	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Azinphos-methyl (Guthion)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156422, Azinphos-methyl (Guthion) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35287
Pollutant:	Azinphos-methyl (Guthion)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156422, Azinphos-methyl (Guthion) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35307
Pollutant:	Azinphos-methyl (Guthion)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156422, Azinphos-methyl (Guthion) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128922
Pollutant:	Azinphos-methyl (Guthion)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Azinphos Methyl. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) expressed as a 4-day average for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156422, Azinphos-methyl (Guthion) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128482
Pollutant:	Azinphos-methyl (Guthion)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Azinphos Methyl. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) expressed as a 4-day average for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156422, Azinphos-methyl (Guthion) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319115
Pollutant:	Azinphos-methyl (Guthion)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Azinphos, methyl, or Azinphos, ethyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156381	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Benzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156381, Benzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34994
Pollutant:	Benzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Benzene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Benzene is 1 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156381, Benzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320270
Pollutant:	Benzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156381, Benzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319831
Pollutant:	Benzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location on this segment of the Colorado River. One water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segement of the river. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Benzene, 0.0005 mg/l Carbon Tetrachloride, 0.0005 mg/l 1,2-Dichloroethane, and 0.001 mg/l 1,1,2,2-Tetrachloroethane (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156382	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Benzo(a)pyrene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156382, Benzo(a)pyrene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321331
Pollutant:	Benzo(a)pyrene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156541	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Benzo(e)Pyrene (4,5-benzopyrene)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156541, Benzo(e)Pyrene (4,5-benzopyrene) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319734
Pollutant:	Benzo(e)Pyrene (4,5-benzopyrene)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, or Terbufos for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156385	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Benzo[g,h,i]perylene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156385, Benzo[g,h,i]perylene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319747
Pollutant:	Benzo[g,h,i]perylene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, or Terbufos for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	170657	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Bifenthrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170657, Bifenthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351620
Pollutant:	Bifenthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Bifenthrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of bifenthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Bifenthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170657, Bifenthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351629
Pollutant:	Bifenthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Bifenthrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of bifenthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Bifenthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170657, Bifenthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351626
Pollutant:	Bifenthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Bifenthrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of bifenthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Bifenthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170657, Bifenthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351622
Pollutant:	Bifenthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Bifenthrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of bifenthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Bifenthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156387	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Biphenyl
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156387, Biphenyl Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319748
Pollutant:	Biphenyl
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, or Terbufos for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156515	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Bolstar
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156515, Bolstar Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320859
Pollutant:	Bolstar
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	77978	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Boron
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of seven water samples exceeded the California State Notification Level criterion. Zero of one water sample exceeded the Water Quality for Agriculture, (published by the Food and Agriculture Organization of the United Nations in 1985) guideline. The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 77978, Boron Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33625
Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Zero of 6 samples exceeded the California State Notification Level criterion.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Waters shall not contain concentrations of chemical constituents shall be present in amounts that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California State Notification Level criterion for boron is 1 mg/L.
Guideline Reference:	Drinking Water Notification Levels and Response Levels
Spatial Representation:	Data was collected at the following station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples were collected on 10/24/2005, 5/2/2006, 5/7/2007, 10/22/2007, 4/21/2008 and 10/28/2008.
Environmental Conditions:
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 77978, Boron Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127273
Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Agricultural Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Boron.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. The guideline for boron is 700 ug/L (0.7 mg/L).
Guideline Reference:	Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 77978, Boron Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127272
Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Boron.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	Drinking water notification levels are published by the Division of Drinking Water. Notification levels are for chemicals for which there is no drinking water MCL. If a notification level is exceeded, local government notification is required and customer notification is recommended. The notification level for Boron is 1 mg/L.
Guideline Reference:	Drinking Water Notification and Response Levels: An Overview
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156493	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Bromobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156493, Bromobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320454
Pollutant:	Bromobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156494	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Bromochloromethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156494, Bromochloromethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320498
Pollutant:	Bromochloromethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156389	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Bromoform
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156389, Bromoform Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320271
Pollutant:	Bromoform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156389, Bromoform Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35226
Pollutant:	Bromoform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Bromoform.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Bromoform criteria for the protection of human health from the consumption of water and organisms is 4.3 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156390	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cadmium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Beneficial use support for Commercial or recreational collection of fish, shellfish, or organisms will be reassessed in a future cycle, if more data are available. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7629
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Hardness Dependant Criterion Maximum Concentration (CMC) for the protection of freshwater aquatic life uses (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128811
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Cadmium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Maximum Contaminant Level for cadmium in the Basin Plan is 0.005 mg/L (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321182
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319619
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333535
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Cadmium .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for cadmium is the probable effect concentration (PEC) of 4.98 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35228
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Cadmium.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Maximum Contaminant Level for cadmium in the Basin Plan is 0.005 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45926
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Cadmium. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for cadmium in fish tissue is 2.2 ppm. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128812
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Cadmium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32833
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the hardness based criteria calculated for cadmium.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128810
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Cadmium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156390, Cadmium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333536
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Cadmium .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for cadmium is the probable effect concentration (PEC) of 4.98 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156391	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Carbon Tetrachloride
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156391, Carbon Tetrachloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320272
Pollutant:	Carbon Tetrachloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156391, Carbon Tetrachloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35292
Pollutant:	Carbon Tetrachloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Carbon tetrachloride.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Carbon tetrachloride is 0.5 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156391, Carbon Tetrachloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319832
Pollutant:	Carbon Tetrachloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location on this segment of the Colorado River. One water sample results could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segement of the river. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Benzene, 0.0005 mg/l Carbon Tetrachloride, 0.0005 mg/l 1,2-Dichloroethane, and 0.001 mg/l 1,1,2,2-Tetrachloroethane (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156524	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Carbophenothion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156524, Carbophenothion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128883
Pollutant:	Carbophenothion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Carbophenothion.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	Drinking water notification levels are published by the Division of Drinking Water and are for chemicals for which there is no drinking water MCL. If a notification level is exceeded, local government notification is required and customer notification is recommended. The criteria for Carbophenothion (Trithion) is 0.007 mg/L.
Guideline Reference:	CDPH Archived Advisory Levels for Drinking Water. Archived Advisory Levels are currently considered Notification Levels.
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156524, Carbophenothion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320699
Pollutant:	Carbophenothion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156393	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chlordane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321183
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45928
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Chlordane, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total chlordane was calculated as the sum of the following chlordane isomers: cis- and trans-chlordane, cis- and trans-nonachlor, and oxychlordane.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total Chlordane concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45927
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Chlordane, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total chlordane was calculated as the sum of the following chlordane isomers: cis- and trans-chlordane, cis- and trans-nonachlor, and oxychlordane.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for total chlordane in fish tissue is 3.9 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45929
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Chlordane, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total chlordane was calculated as the sum of the following chlordane isomers: cis- and trans-chlordane, cis- and trans-nonachlor, and oxychlordane.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total Chlordane concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33174
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	The reporting limit for all 6 of the non-detect samples was greater than the criteria and thus the data were not used in this assessment.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The total chlordane criterion for the protection of human health from the consumption of water and organisms is 0.00057 ug/L. This value corresponds to total chlordane, eg., the sum of cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, and oxychlordane. (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD Colorado River at Nevada State Line
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127337
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Chlordane.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The chlordane criteria for the protection of human health from the consumption of water and organisms is 0.00057 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320860
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320252
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156393, Chlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32993
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the criterion continuous concentration for chlordane (total). Total chlordane is assessed as the sum of cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, and oxychlordane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The chlordane criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0043 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD Colorado River at Nevada State Line
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156503	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chlorfenvinphos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156503, Chlorfenvinphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320512
Pollutant:	Chlorfenvinphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156394	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chloride
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156394, Chloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128102
Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Chloride.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used: 500 mg/l Chloride (CCR, title 22).
Guideline Reference:	California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156394, Chloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128104
Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Chloride.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Chloride criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 230000 ug/L (230 mg/L)(USEPA National Recommended Water Quality Criteria, 2006).
Objective/Criterion Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156394, Chloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33104
Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the criteria of 230 mg/L.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Chloride criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 230000 ug/L (230 mg/L)(USEPA National Recommended Water Quality Criteria, 2006).
Objective/Criterion Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected at station713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples were collected on 10/24/2005, 5/2/2006, 5/7/2007, 10/22/2007, 4/21/2008, and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008).
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156394, Chloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320072
Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156394, Chloride Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128101
Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Chloride.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Chloride criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 230000 ug/L (230 mg/L)(USEPA National Recommended Water Quality Criteria, 2006).
Objective/Criterion Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156395	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chlorobenzene (mono)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156395, Chlorobenzene (mono) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35317
Pollutant:	Chlorobenzene (mono)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Chlorobenzene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for monochlorobenzene is 70 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156395, Chlorobenzene (mono) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321192
Pollutant:	Chlorobenzene (mono)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156395, Chlorobenzene (mono) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321029
Pollutant:	Chlorobenzene (mono)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156396	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chloroform
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156396, Chloroform Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35001
Pollutant:	Chloroform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Chloroform.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for total trihalomethanes is 80 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156396, Chloroform Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320509
Pollutant:	Chloroform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	164788	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chlorpyrifos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 164788, Chlorpyrifos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128957
Pollutant:	Chlorpyrifos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Chlorpyrifos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The freshwater criterion continuous concentration to protect aquatic organisms is 0.014 ug/L (Siepmann and Finlayson 2000).
Guideline Reference:	Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 164788, Chlorpyrifos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35186
Pollutant:	Chlorpyrifos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples total were collected. None of the samples were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005).
Guideline Reference:	Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game (with minor corrections to significant figures as described in Beaulaurier et al., 2005).
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 164788, Chlorpyrifos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128225
Pollutant:	Chlorpyrifos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Chlorpyrifos.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA drinking water health advisory for lifetime exposure to chlorpyrifos is 0.002 mg/L.
Guideline Reference:	2012 Edition of the Drinking Water Standards and Health Advisories
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 164788, Chlorpyrifos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35189
Pollutant:	Chlorpyrifos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples total were collected. None of the samples were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005).
Guideline Reference:	Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game (with minor corrections to significant figures as described in Beaulaurier et al., 2005).
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 164788, Chlorpyrifos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127371
Pollutant:	Chlorpyrifos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Chlorpyrifos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The freshwater criterion continuous concentration to protect aquatic organisms is 0.014 ug/L (Siepmann and Finlayson 2000).
Guideline Reference:	Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 164788, Chlorpyrifos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45930
Pollutant:	Chlorpyrifos
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Chlorpyrifos. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for chlorpyrifos in fish tissue is 660 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156551	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chlorpyrifos, methyl
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). LOE Removal(s): 29449; LOE Replacement(s): 320307
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156551, Chlorpyrifos, methyl Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127866
Pollutant:	Chlorpyrifos, methyl
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Chlorpyrifos Methyl.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Chlorpyrifos Methyl is the USEPA Aquatic Life Benchmark of 0.085 ug/L for an invertebrate (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156551, Chlorpyrifos, methyl Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127867
Pollutant:	Chlorpyrifos, methyl
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Chlorpyrifos Methyl.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Chlorpyrifos Methyl is the USEPA Aquatic Life Benchmark of 0.085 ug/L for an invertebrate (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156551, Chlorpyrifos, methyl Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320307
Pollutant:	Chlorpyrifos, methyl
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156557	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chromium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156557, Chromium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321292
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156557, Chromium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320253
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156557, Chromium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333557
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Chromium .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for chromium is the probable effect concentration (PEC) of 111 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156557, Chromium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333549
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Chromium .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for chromium is the probable effect concentration (PEC) of 111 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	71637	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chromium (total)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Seven lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the samples exceed the water quality objective. Sample sizes for each matrix, fraction, beneficial use and objective were less than 16. The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 71637, Chromium (total) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128708
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Chromium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 71637, Chromium (total) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34302
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the MCL for total Chromium.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Department of Public Health's Maximum Contaminate Level (MCL) in drinking water for Total Chromium is 0.05mg/L or 50ug/L.
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/05 and 10/28/08.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 71637, Chromium (total) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128706
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Chromium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 71637, Chromium (total) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128707
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Chromium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for total chromium is 0.05 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 71637, Chromium (total) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33923
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the hardness based criteria calculated for chromium III or the criteria for chromium VI.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each chromium III sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion. The criterion continuous concentration (4-day average) to protect aquatic life in freshwater for chromium VI is 11 ug/L and is not hardness dependent.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/05 and 10/28/08.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	170664	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cinerin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170664, Cinerin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351646
Pollutant:	Cinerin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Cinerin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for cinerin is the USEPA Aquatic Life Benchmark of 0.04 ug/L for freshwater invertebrates (chronic) and is the sum of cinerin-1 and cinerin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170664, Cinerin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351647
Pollutant:	Cinerin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Cinerin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for cinerin is the USEPA Aquatic Life Benchmark of 0.04 ug/L for freshwater invertebrates (chronic) and is the sum of cinerin-1 and cinerin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156516	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Ciodrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156516, Ciodrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320861
Pollutant:	Ciodrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156400	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Copper
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Implementation Action Other than TMDL:	LOEs 7616 and 319076 result in double counting.
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7616
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule Hardness Dependent Criterion Maximum Concentration (CMC) for the protection of freshwater aquatic life uses (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333594
Pollutant:	Copper
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Copper .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for copper is the probable effect concentration (PEC) of 149 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128266
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Copper.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35275
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Copper.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for copper is 1.0 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128268
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Copper.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Secondary MCL for copper is 1.0 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333590
Pollutant:	Copper
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Copper .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for copper is the probable effect concentration (PEC) of 149 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128267
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Copper.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32855
Pollutant:	Copper, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the hardness based criteria calculated for copper.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320086
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156400, Copper Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319076
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the USFWS Biological Effect Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	United State Fish and Wildlife Service (USFWS) Biological Effect Criteria for the protection of aquatic life uses were used for the following constituents: 0.25 mg/l Arsenic, and 15 mg/l Copper (USFWS, 1998).
Guideline Reference:	Guidelines for Interpretation of the Biological Effect of Selected Constituents in Biota, Water, and Sediment. US Department of Interior report.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	102982	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Coumaphos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line(s) of evidence is necessary to assess listing status. Two lines of evidence is available in the administrative record to assess this pollutant. Zero of zero samples exceed the USEPA Aquatic Life Benchmark for an invertebrate (chronic) for the beneficial uses assessed. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5 Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of zero samples exceed the USEPA Aquatic Life Benchmark for an invertebrate (chronic) for the beneficial uses assessed. Although one sample were collected, it was not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5 This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 102982, Coumaphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127015
Pollutant:	Coumaphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Coumaphos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Coumaphos is the USEPA Aquatic Life Benchmark of 0.0337 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 102982, Coumaphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128970
Pollutant:	Coumaphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Coumaphos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Coumaphos is the USEPA Aquatic Life Benchmark of 0.0337 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156401	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cumene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156401, Cumene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320455
Pollutant:	Cumene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156504	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cuomaphos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156504, Cuomaphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320308
Pollutant:	Cuomaphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	78176	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cyanazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Zero of two sample(s) exceed the water quality objectives for each of the two beneficial uses assessed: "Cold Freshwater Habitat" and "Warm Freshwater Habitat" Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of two sample(s) exceed the water quality objectives for each of the two beneficial uses assessed: "Cold Freshwater Habitat" and "Warm Freshwater Habitat" The sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 78176, Cyanazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127904
Pollutant:	Cyanazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Cyanazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	According to the USEPA Office of Pesticide Programs Ecotoxicity database, the aquatic life EC50 for Cyanazine is 4.8 ug/L.
Guideline Reference:	OPP Pesticide Ecotoxicity Database.
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 78176, Cyanazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35320
Pollutant:	Cyanazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Cyanazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental phyusiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	According to the USEPA Office of Pesticide Programs Ecotoxicity database, the aquatic life EC50 for Cyanazine is 4.8 ug/L.
Guideline Reference:	OPP Pesticide Ecotoxicity Database.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 78176, Cyanazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127905
Pollutant:	Cyanazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Cyanazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	According to the USEPA Office of Pesticide Programs Ecotoxicity database, the aquatic life EC50 for Cyanazine is 4.8 ug/L.
Guideline Reference:	OPP Pesticide Ecotoxicity Database.
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 78176, Cyanazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35319
Pollutant:	Cyanazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Cyanazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental phyusiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	According to the USEPA Office of Pesticide Programs Ecotoxicity database, the aquatic life EC50 for Cyanazine is 4.8 ug/L.
Guideline Reference:	OPP Pesticide Ecotoxicity Database.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	170658	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cyfluthrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 170658, Cyfluthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351672
Pollutant:	Cyfluthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cyfluthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cyfluthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170658, Cyfluthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351663
Pollutant:	Cyfluthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cyfluthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cyfluthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170658, Cyfluthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351664
Pollutant:	Cyfluthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cyfluthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cyfluthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170658, Cyfluthrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351668
Pollutant:	Cyfluthrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cyfluthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cyfluthrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	170659	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cyhalothrin, Lambda
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 170659, Cyhalothrin, Lambda Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351849
Pollutant:	Cyhalothrin, Lambda
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for lambda-cyhalothrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of lambda-cyhalothrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Lambda-cyhalothrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170659, Cyhalothrin, Lambda Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351854
Pollutant:	Cyhalothrin, Lambda
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for lambda-cyhalothrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of lambda-cyhalothrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Lambda-cyhalothrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170659, Cyhalothrin, Lambda Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351845
Pollutant:	Cyhalothrin, Lambda
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for lambda-cyhalothrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of lambda-cyhalothrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Lambda-cyhalothrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170659, Cyhalothrin, Lambda Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351853
Pollutant:	Cyhalothrin, Lambda
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for lambda-cyhalothrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of lambda-cyhalothrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Lambda-cyhalothrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	169366	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Cypermethrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 169366, Cypermethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351689
Pollutant:	Cypermethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cypermethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cypermethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169366, Cypermethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351709
Pollutant:	Cypermethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cypermethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cypermethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169366, Cypermethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351696
Pollutant:	Cypermethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cypermethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cypermethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169366, Cypermethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351690
Pollutant:	Cypermethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cypermethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Cypermethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	170161	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	DDD (Dichlorodiphenyldichloroethane)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170161, DDD (Dichlorodiphenyldichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34527
Pollutant:	DDD (Dichlorodiphenyldichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	The method detection limit for all 6 of the non-detect samples was greater than the criteria: thus the data was not used in this assessment.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 4,4'-DDD criterion for the protection of human health from the consumption of water and organisms is 0.00031 ug/L (USEPA Nationally Recommended Criteria, 2006).
Objective/Criterion Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 170161, DDD (Dichlorodiphenyldichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128649
Pollutant:	DDD (Dichlorodiphenyldichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for DDD (Dichlorodiphenyldichloroethane).
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 4,4'-DDD criterion for the protection of human health from the consumption of water and organisms is 0.00083 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	170163	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	DDE (Dichlorodiphenyldichloroethylene)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170163, DDE (Dichlorodiphenyldichloroethylene) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127795
Pollutant:	DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for DDE (Dichlorodiphenyldichloroethylene).
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The DDE(p,p) criteria for the protection of human health from the consumption of water and organisms is 0.00059 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 170163, DDE (Dichlorodiphenyldichloroethylene) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34528
Pollutant:	DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	The method detection limit for all 6 of the non-detect samples was greater than the criteria: thus the data was not used in this assessment.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 4,4'-DDE criterion for the protection of human health from the consumption of water and organisms is 0.00022 ug/L (USEPA Nationally Recommended Criteria, 2006).
Objective/Criterion Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	170159	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34525
Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	The detection limit for DDT(o,p) is 0.001 ug/l, and the reporting limit for that is 0.002 ug/l. Since the WQS is smaller than the reporting limit, none of samples can be counted. In addition the detection limit for DDT(p,p') is 0.002 ug/l and the reporting limit is 0.005 ug/l, none of the samples can be counted. The water body was assessed for the sum of DDT(o,p') and DDT(p,p').
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 4,4' DDT criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7641
Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentration (CMC) for pp'-DDT of 1.1 ug/l for the protection of freshwater aquatic life uses (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128415
Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for DDT (Dichlorodiphenyltrichloroethane).
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34526
Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	The method detection limit for all 6 of the non-detect samples was greater than the criteria: thus the data was not used in this assessment.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 4,4' DDT criterion for the protection of human health from the consumption of water and organisms is 0.00022 ug/L (USEPA Nationally Recommended Criteria, 2006).
Objective/Criterion Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128418
Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for DDT (Dichlorodiphenyltrichloroethane).
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The DDT(p,p) criteria for the protection of human health from the consumption of water and organisms is 0.00059 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45931
Pollutant:	Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for DDT, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total DDT was calculated as the sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for total DDT in fish tissue is 15 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45932
Pollutant:	Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for DDT, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total DDT was calculated as the sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total DDT concentration of 1000 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128417
Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for DDT (Dichlorodiphenyltrichloroethane).
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 170159, DDT (Dichlorodiphenyltrichloroethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45933
Pollutant:	Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for DDT, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total DDT was calculated as the sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total DDT concentration of 1000 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156403	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dacthal
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available\ LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156403, Dacthal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320862
Pollutant:	Dacthal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156403, Dacthal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351716
Pollutant:	Dacthal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Dacthal.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Dacthal is the USEPA Aquatic Life Benchmark of >11000 ug/L for a nonvascular plant (acute) and vascular plant (acute). The benchmark was derived from a greater-than value (for example, > 265,000) and may overestimate toxicity.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156403, Dacthal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128611
Pollutant:	Dacthal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dacthal.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Dacthal is the USEPA Aquatic Life Benchmark of > 11000 ug/L for a nonvascular plant (acute) and vascular plant (acute). The benchmark was derived from a 'greater-than' value (for example, > 265,000) and may overestimate toxicity.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156403, Dacthal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35342
Pollutant:	Dacthal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Dacthal.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The National Recommended Water Quality Criteria for dacthal (DCPA) for the consumption of water and fish is 0.008 ug/L.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156403, Dacthal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351717
Pollutant:	Dacthal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Dacthal.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Dacthal is the USEPA Aquatic Life Benchmark of >11000 ug/L for a nonvascular plant (acute) and vascular plant (acute). The benchmark was derived from a greater-than value (for example, > 265,000) and may overestimate toxicity.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156403, Dacthal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128661
Pollutant:	Dacthal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dacthal.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Dacthal is the USEPA Aquatic Life Benchmark of > 11000 ug/L for a nonvascular plant (acute) and vascular plant (acute). The benchmark was derived from a 'greater-than' value (for example, > 265,000) and may overestimate toxicity.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156403, Dacthal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128610
Pollutant:	Dacthal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dacthal.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA drinking water health advisory for lifetime exposure to DCPA is 0.007 mg/L.
Guideline Reference:	2012 Edition of the Drinking Water Standards and Health Advisories
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	169367	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Deltamethrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 169367, Deltamethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351730
Pollutant:	Deltamethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169367, Deltamethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351734
Pollutant:	Deltamethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169367, Deltamethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351726
Pollutant:	Deltamethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169367, Deltamethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351719
Pollutant:	Deltamethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	103004	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Demeton
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the samples exceed the water quality objective. Sample sizes for each matrix, fraction, beneficial use and objective were less than 16. The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 103004, Demeton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127507
Pollutant:	Demeton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Demeton, Total.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Demeton, calculated using the IRIS Reference Dose, is 0.3 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.00004 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 103004, Demeton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127508
Pollutant:	Demeton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Demeton, Total.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	National Recommended Water Quality Criteria Continuous Concentrations (4-day average concentrations) for freshwater aquatic organisms exposure to Demeton is 0.1 ug/L.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 103004, Demeton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127509
Pollutant:	Demeton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Demeton, Total.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	National Recommended Water Quality Criteria Continuous Concentrations (4-day average concentrations) for freshwater aquatic organisms exposure to Demeton is 0.1 ug/L.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156405	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Demeton s
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156405, Demeton s Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320874
Pollutant:	Demeton s
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	164789	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Diazinon
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 164789, Diazinon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35192
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Diazinon.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).
Guideline Reference:	Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 164789, Diazinon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127629
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Diazinon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).
Guideline Reference:	Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 164789, Diazinon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127631
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Diazinon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA drinking water health advisory for diazinon is 1.4 µg/L.
Guideline Reference:	2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 164789, Diazinon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7687
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDFG Hazardous Assessment Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Fish and Games (CDFG) Hazardous Assessment Criteria of 0.16 ug/l for the protection of aquatic life uses (Siepmann and Finlayson, 2000).
Guideline Reference:	Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 164789, Diazinon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35195
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Diazinon.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).
Guideline Reference:	Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 164789, Diazinon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45934
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Diazinon. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for diazinon in fish tissue is 1,500 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 164789, Diazinon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127630
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Diazinon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).
Guideline Reference:	Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156525	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dichlofenthion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156525, Dichlofenthion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320700
Pollutant:	Dichlofenthion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156408	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dichlorobromomethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156408, Dichlorobromomethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320285
Pollutant:	Dichlorobromomethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156408, Dichlorobromomethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35185
Pollutant:	Dichlorobromomethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Bromodichloromethane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Bromodichloromethane criteria is 0.56 ug/L for the protection of human health from consumption of water and organisms (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156409	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dichlorodifluoromethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156409, Dichlorodifluoromethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320042
Pollutant:	Dichlorodifluoromethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Methyl Chloride, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, or 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156410	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dichloromethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156410, Dichloromethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319064
Pollutant:	Dichloromethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location along this segment of the Colorado River. This sample did not exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 48 ug/l Methyl Bromide, and 5 ug/l Dichloromethane (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. A water sample was collected in 5/2002.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156411	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dichlorvos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156411, Dichlorvos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351746
Pollutant:	Dichlorvos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156411, Dichlorvos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351744
Pollutant:	Dichlorvos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156411, Dichlorvos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320875
Pollutant:	Dichlorvos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156411, Dichlorvos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127028
Pollutant:	Dichlorvos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156411, Dichlorvos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127060
Pollutant:	Dichlorvos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156505	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dicrotophos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). LOE Removal(s): 29449; LOE Replacement(s): 320309
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156505, Dicrotophos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127771
Pollutant:	Dicrotophos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dicrotophos.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Dicrotophos calculated using the IRIS Reference Dose, is 0.7 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.0001 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156505, Dicrotophos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320309
Pollutant:	Dicrotophos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156412	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dieldrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127158
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dieldrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35302
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Dieldrin criteria for the protection of human health from the consumption of water and organisms is 0.00014 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128923
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dieldrin. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Dieldrin criteria for the protection of human health from the consumption of water and organisms is 0.00014 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35324
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Dieldrin.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320254
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45937
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Dieldrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Dieldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45935
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Dieldrin. One composite (6 fish per composite) were generated from one species: largemouth bass. One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for dieldrin in fish tissue is 0.32 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45936
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Dieldrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Dieldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127160
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dieldrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156412, Dieldrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35301
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Dieldrin.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156485	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dimethoate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156485, Dimethoate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351751
Pollutant:	Dimethoate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Dimethoate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156485, Dimethoate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351752
Pollutant:	Dimethoate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Dimethoate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156485, Dimethoate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128132
Pollutant:	Dimethoate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dimethoate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156485, Dimethoate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320876
Pollutant:	Dimethoate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156485, Dimethoate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128131
Pollutant:	Dimethoate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Dimethoate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156553	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dioxathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156553, Dioxathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320701
Pollutant:	Dioxathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156413	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Disulfoton
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). LOE Removal(s): 29450; LOE Replacement(s): 320877
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156413, Disulfoton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128934
Pollutant:	Disulfoton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Disulfoton. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Disulfoton is the USEPA Aquatic Life Benchmark of 0.01 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156413, Disulfoton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128935
Pollutant:	Disulfoton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Disulfoton. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Disulfoton is the USEPA Aquatic Life Benchmark of 0.01 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156413, Disulfoton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320877
Pollutant:	Disulfoton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156414	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dyfonate (Fonofos or Fonophos)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156414, Dyfonate (Fonofos or Fonophos) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320310
Pollutant:	Dyfonate (Fonofos or Fonophos)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	164790	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Endosulfan
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 164790, Endosulfan Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45939
Pollutant:	Endosulfan
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endosulfan, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total endosulfan was calculated as the sum of endosulfan l and endosulfan ll.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total Endosulfan concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 164790, Endosulfan Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45938
Pollutant:	Endosulfan
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endosulfan, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total endosulfan was calculated as the sum of endosulfan l and endosulfan ll.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for endosulfan (l and ll) in fish tissue is 13,000 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 164790, Endosulfan Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33089
Pollutant:	Endosulfan
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the criteria.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The endosulfan criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L. This value corresponds to the sum of alpha-endosulfan and beta-endosulfan (USEPA National Recommended Water Quality Criteria, 2006).
Objective/Criterion Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected at station713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples were collected on 10/24/2005, 5/2/2006, 5/7/2007, 10/22/2007, 4/21/2008, and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008).
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 164790, Endosulfan Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45940
Pollutant:	Endosulfan
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endosulfan, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total endosulfan was calculated as the sum of endosulfan l and endosulfan ll.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total Endosulfan concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156415	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Endosulfan sulfate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156415, Endosulfan sulfate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321040
Pollutant:	Endosulfan sulfate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156415, Endosulfan sulfate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127284
Pollutant:	Endosulfan sulfate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endosulfan Sulfate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan Sulfate criteria for endosulfan sulfate to protect human health for waters that include the designated use of MUN is 110 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156415, Endosulfan sulfate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35055
Pollutant:	Endosulfan sulfate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endosulfan sulfate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan Sulfate criteria for endosulfan sulfate to protect human health for waters that include the designated use of MUN is 110 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156416	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Endrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35064
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endrin.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127179
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35065
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endrin.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endrin criteria for the protection of human health from the consumption of water and organisms is 0.76 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127181
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35071
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endrin.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320255
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321041
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321293
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127180
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endrin criteria for the protection of human health from the consumption of water and organisms is 0.76 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45942
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Endrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45941
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for endrin in fish tissue is 660 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156416, Endrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45943
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endrin. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Endrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156517	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Endrin Ketone
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156517, Endrin Ketone Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320889
Pollutant:	Endrin Ketone
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156417	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Endrin aldehyde
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollution
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156417, Endrin aldehyde Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128148
Pollutant:	Endrin aldehyde
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endrin Aldehyde.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endrin Aldehyde criteria for the protection of human health from consumption of water and organisms is 0.76 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156417, Endrin aldehyde Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321042
Pollutant:	Endrin aldehyde
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	170661	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Esfenvalerate/Fenvalerate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170661, Esfenvalerate/Fenvalerate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351773
Pollutant:	Esfenvalerate/Fenvalerate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for esfenvalerate is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of esfenvalerate were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Esfenvalerate
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170661, Esfenvalerate/Fenvalerate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351768
Pollutant:	Esfenvalerate/Fenvalerate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for esfenvalerate is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of esfenvalerate were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Esfenvalerate
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170661, Esfenvalerate/Fenvalerate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351776
Pollutant:	Esfenvalerate/Fenvalerate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for esfenvalerate is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of esfenvalerate were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Esfenvalerate
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170661, Esfenvalerate/Fenvalerate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351777
Pollutant:	Esfenvalerate/Fenvalerate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for esfenvalerate is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of esfenvalerate were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Esfenvalerate
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156478	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Ethion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156478, Ethion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351784
Pollutant:	Ethion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Ethion. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for ethion is the USEPA Aquatic Life Benchmark of 0.028 ug/L for invertebrates (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156478, Ethion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351785
Pollutant:	Ethion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Ethion. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for ethion is the USEPA Aquatic Life Benchmark of 0.028 ug/L for invertebrates (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156478, Ethion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127758
Pollutant:	Ethion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ethion.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Ethion, calculated using the IRIS Reference Dose, is 3.5 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.0005 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156478, Ethion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320702
Pollutant:	Ethion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156487	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Ethoprop
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). LOE Removal(s): 29450; LOE Replacement(s): 320890
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156487, Ethoprop Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128730
Pollutant:	Ethoprop
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ethoprop.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Ethoprop is the USEPA Aquatic Life Benchmark of 0.8 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156487, Ethoprop Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128729
Pollutant:	Ethoprop
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ethoprop.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Ethoprop is the USEPA Aquatic Life Benchmark of 0.8 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156487, Ethoprop Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320890
Pollutant:	Ethoprop
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156419	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Ethylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156419, Ethylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321053
Pollutant:	Ethylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156419, Ethylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321302
Pollutant:	Ethylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156419, Ethylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35119
Pollutant:	Ethylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Ethylbenzene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Ethylbenzene is 300 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156418	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Ethylene dibromide
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156418, Ethylene dibromide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320510
Pollutant:	Ethylene dibromide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156518	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Famphur
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156518, Famphur Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320891
Pollutant:	Famphur
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156506	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Fenchlorphos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156506, Fenchlorphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320322
Pollutant:	Fenchlorphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156526	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Fenitrothion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156526, Fenitrothion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127829
Pollutant:	Fenitrothion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Fenitrothion.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Fenitrothion is the USEPA Aquatic Life Benchmark of 0.087 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156526, Fenitrothion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320713
Pollutant:	Fenitrothion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156526, Fenitrothion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127830
Pollutant:	Fenitrothion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Fenitrothion.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Fenitrothion is the USEPA Aquatic Life Benchmark of 0.087 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	170660	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Fenpropathrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170660, Fenpropathrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351789
Pollutant:	Fenpropathrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenpropathrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.0015 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2007-10-22 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170660, Fenpropathrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351792
Pollutant:	Fenpropathrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenpropathrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.0015 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170660, Fenpropathrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351790
Pollutant:	Fenpropathrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenpropathrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.0015 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170660, Fenpropathrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351805
Pollutant:	Fenpropathrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenpropathrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.0015 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2007-10-22 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156527	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Fensulfothion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156527, Fensulfothion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320714
Pollutant:	Fensulfothion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156528	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Fenthion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156528, Fenthion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320715
Pollutant:	Fenthion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156528, Fenthion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128962
Pollutant:	Fenthion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenthion. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Fenthion is the USEPA Aquatic Life Benchmark of 0.013 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156528, Fenthion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127934
Pollutant:	Fenthion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Fenthion. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Fenthion is the USEPA Aquatic Life Benchmark of 0.013 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156420	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Fluoranthene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156420, Fluoranthene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321054
Pollutant:	Fluoranthene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156421	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Fluorene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156421, Fluorene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321055
Pollutant:	Fluorene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156423	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Heptachlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45947
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Heptachlor. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Heptachlor concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45948
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Heptachlor. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Heptachlor concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35091
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Heptachlor.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128054
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Heptachlor.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35092
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor criteria for the protection of human health from the consumption of water and organisms is 0.00021 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127025
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor criteria for the protection of human health from the consumption of water and organisms is 0.00021 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128055
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Heptachlor.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35096
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Heptachlor.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321303
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156423, Heptachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320266
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156424	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Heptachlor epoxide
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	126887
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Heptachlor Epoxide.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor Epoxide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320267
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321312
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35148
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Heptachlor epoxide.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor Epoxide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45950
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Heptachlor epoxide. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Heptachlor Epoxide concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128512
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor Epoxide. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor Epoxide criteria for the protection of human health from the consumption of water and organisms is 0.00010 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45951
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Heptachlor epoxide. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Heptachlor Epoxide concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	126888
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Heptachlor Epoxide.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor Epoxide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35131
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Heptachlor epoxide.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor Epoxide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35132
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Heptachlor Epoxide criteria for the protection of human health from the consumption of water and organisms is 0.00010 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156424, Heptachlor epoxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45949
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Heptachlor epoxide. One composite (6 fish per composite) were generated from one species: largemouth bass. One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for heptachlor epoxide in fish tissue is 0.93 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Public Health Goal for Heptachlor and Heptachlor Epoxide in Drinking Water
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156425	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Hexachlorobenzene/ HCB
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)., LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156425, Hexachlorobenzene/ HCB Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128953
Pollutant:	Hexachlorobenzene/ HCB
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Hexachlorobenzene. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Hexachlorobenzene criteria for the protection of human health from the consumption of water and organisms is 0.00075 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156425, Hexachlorobenzene/ HCB Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321313
Pollutant:	Hexachlorobenzene/ HCB
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156425, Hexachlorobenzene/ HCB Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35523
Pollutant:	Hexachlorobenzene/ HCB
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Hexachlorobenzene criteria for the protection of human health from the consumption of water and organisms is 0.00075 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156425, Hexachlorobenzene/ HCB Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45960
Pollutant:	Hexachlorobenzene/ HCB
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Hexachlorobenzene. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for hexachlorobenzene in fish tissue is 2.8 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156426	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Hexachlorobutadiene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156426, Hexachlorobutadiene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35565
Pollutant:	Hexachlorobutadiene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Hexachlorobutadiene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Hexachlorobutadiene criteria for the protection of human health from the consumption of water and organisms is 0.44 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156426, Hexachlorobutadiene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320286
Pollutant:	Hexachlorobutadiene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	69961	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Indicator Bacteria
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Six lines of evidence are available in the administrative record to assess this pollutant. One of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 4 water samples exceeded the Basin Plan Enterococcus water quality objectives for water contact recreation. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 69961, Indicator Bacteria Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7610
Pollutant:	Enterococcus
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Non-Contact Recreation
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected biannually from 5/2002 through 11/2003 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan:In the Colorado River the maximum allowable Enterococcus density is 305 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 11/2003 from the Nevada Border. Samples were generally collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 69961, Indicator Bacteria Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7607
Pollutant:	Enterococcus
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Water Contact Recreation
Number of Samples:	4
Number of Exceedances:	1
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected biannually from 5/2002 through 11/2003 at 1 location along this segment of the Colorado River. Of these total samples, 1 exceeded the Basin Plan Objective. The exceedance was found in a sample collected on 11/03/2003 from near the Nevada Border (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan:In the Colorado River the maximum allowable Enterococcus density is 61 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 11/2003 from the Nevada Border. Samples were generally collected in May and October. The exceedance was found in a sample collected on 11/03/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 69961, Indicator Bacteria Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7694
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Water Contact Recreation
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected biannually from 5/2002 through 11/2003 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan:In the Colorado River the maximum allowable E. coli density is 235 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the Caliornia Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 11/2003 from the Nevada Border. Samples were generally collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 69961, Indicator Bacteria Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	126148
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Water Contact Recreation
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PATHOGEN MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).
Objective/Criterion Reference:	Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s), station(s): 713CRNVBD
Temporal Representation:	The samples were collected between the days of 2013-04-15 and 2013-04-15 .
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 69961, Indicator Bacteria Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7702
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Non-Contact Recreation
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected biannually from 5/2002 through 11/2003 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan:In the Colorado River the maximum allowable E. coli density is 1175 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 11/2003 from the Nevada Border. Samples were generally collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 69961, Indicator Bacteria Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	129096
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Water Contact Recreation
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	The sample collected did not exceed the E. coli objective.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The E. coli concentration shall not exceed more than 235/100ml. Basin Plan for the Colorado River Basin.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The sample was collected from the Colorado River at Nevada State Line station 713CRNVBD.
Temporal Representation:	The sample was collected on 4/15/2013 from the Colorado River at Nevada State Line station 713CRNVBD.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	170665	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Jasmolin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170665, Jasmolin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351816
Pollutant:	Jasmolin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Jasmolin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for jasmolin is the USEPA Aquatic Life Benchmark of 0.04 ug/L for freshwater invertebrates (chronic) and is the sum of jasmolin-1 and jasmolin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170665, Jasmolin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351829
Pollutant:	Jasmolin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Jasmolin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for jasmolin is the USEPA Aquatic Life Benchmark of 0.04 ug/L for freshwater invertebrates (chronic) and is the sum of jasmolin-1 and jasmolin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156429	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Lead
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319769
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128332
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Lead.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333662
Pollutant:	Lead
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Lead .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for lead is the probable effect concentration (PEC) of 128 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333656
Pollutant:	Lead
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Lead .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for lead is the probable effect concentration (PEC) of 128 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128334
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Lead.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Maximum Contaminant Level for lead in the Basin Plan is 0.015 mg/L (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319620
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32918
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the hardness based criteria calculated for lead.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line)
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156429, Lead Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128333
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Lead.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156507	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Leptophos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156507, Leptophos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320323
Pollutant:	Leptophos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156430	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319635
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321322
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35123
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for HCH, gamma.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The gamma-BHC (Lindane) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127644
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for HCH, gamma-.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The gamma-BHC (Lindane) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127643
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for HCH, gamma-.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The BHC, gamma(Lindane) criteria for the protection of human health from the consumption of water and organisms is 0.019 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35104
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for HCH, gamma.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The BHC, gamma(Lindane) criteria for the protection of human health from the consumption of water and organisms is 0.019 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127642
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for HCH, gamma-.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The gamma-BHC (Lindane) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L. Footnote g specifies that (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35103
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for HCH, gamma.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The gamma-BHC (Lindane) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45946
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for HCH, gamma. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Lindane concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45945
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for HCH, gamma. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Lindane concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156430, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45944
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for HCH, gamma. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for lindane in fish tissue is 4.6 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156431	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Malathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156431, Malathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127031
Pollutant:	Malathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Malathion. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The UC Davis Criteria for Malathion for the protection of aquatic organisms is a 4 day average of 0.028 ug/L.
Guideline Reference:	Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156431, Malathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128558
Pollutant:	Malathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Malathion. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The UC Davis Criteria for Malathion for the protection of aquatic organisms is a 4 day average of 0.028 ug/L.
Guideline Reference:	Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156431, Malathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320716
Pollutant:	Malathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156431, Malathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351859
Pollutant:	Malathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Malathion. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The UC Davis Criteria for Malathion for the protection of aquatic organisms is a 4 day average of 0.028 ug/L.
Guideline Reference:	Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156431, Malathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351857
Pollutant:	Malathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Malathion. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The UC Davis Criteria for Malathion for the protection of aquatic organisms is a 4 day average of 0.028 ug/L.
Guideline Reference:	Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156432	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Manganese
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156432, Manganese Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128635
Pollutant:	Manganese
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Manganese.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Secondary MCL for manganese is 0.5 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156432, Manganese Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35628
Pollutant:	Manganese
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Manganese.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for manganese is 0.05 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156432, Manganese Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320202
Pollutant:	Manganese
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	172152	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Mercury
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under sections 3.1 and 3.5 of the Listing Policy. Under sections 3.1 and 3.5 a single line of evidence is necessary to assess listing status. Nine lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective(s). LOEs 27150, 35633, 46760, and 127323 for COMM water data were retired due to undesignated COMM. LOE 7650 is replaced with LOE 321066 and LOE 7673 is replaced with LOE 321323 due to a multipollutant LOE being split into LOEs for individual pollutants. LOE 45961 is replaced with LOEs 133288 and 133324 due to reassessment of previous data due to adoption of the statewide mercury objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the 21 water samples exceeded the CTR criteria for Municipal and Domestic supply. None of the 7 water samples exceeded the criteria for Warm Freshwater Habitat. None of one tissue sample(s) exceeded the Statewide Sport Fish Water Quality Objective for the protection of Commercial and Sport Fishing (CDFW). None of one tissue sample(s) exceeded the Statewide Sport Fish Water Quality Objective for the protection of Wildlife Habitat. This sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127324
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Mercury.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The mercury criteria for the protection of human health from the consumption of water and organisms for mercury is 0.050 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35654
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Mercury.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The mercury criteria for the protection of human health from the consumption of water and organisms for mercury is 0.050 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7638
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the NRWQC criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	National Recommended Water Quality Criteria (NRWQC) Criterion Maximum Concentration (CMC) of 1.4 ug/l for the protection of freshwater aquatic life uses (USEPA, 2002).
Objective/Criterion Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	133194
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality standard for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 13 fish were aggregated into 1 annual averages, which consisted of 2 fish species (7 composite(s) of Largemouth Bass each composed of 1 fish per composite, 1 composite(s) of Largemouth Bass each composed of 6 fish per composite).
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The Statewide Sport Fish Water Quality Objective for the protection of the Commercial and Sport Fishing beneficial comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027.
Guideline Reference:	Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
Spatial Representation:	Data was collected from 1 station(s) with the station code(s): 713CRNVBD.
Temporal Representation:	Data for this line of evidence were collected between 2004-12-09 and 2004-12-09
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	133288
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality standard for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 1 fish were aggregated into 1 annual averages, which consisted of 1 fish species (1 composite(s) of Largemouth Bass each composed of 1 fish per composite). This LOE does not contain data from fish whos average length was outside of the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The Statewide Sport Fish Water Quality Objective for the protection of the Commercial and Sport Fishing beneficial comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027.
Guideline Reference:	Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
Spatial Representation:	Data was collected from 1 station(s) with the station code(s): 713CRNVBD.
Temporal Representation:	Data for this line of evidence were collected between 2004-12-09 and 2004-12-09
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	132951
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Wildlife Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality standard for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 1 fish were aggregated into 1 annual averages, which consisted of 1 fish species (1 composite(s) of Largemouth Bass each composed of 1 fish per composite). This LOE does not contain data from fish whos average length was outside of the legal size limits as described by the California Department of Fish and Wildlife Fishing Regulations.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The Statewide Sport Fish Water Quality Objective for the protection of Wildlife Habitat comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. If trophic level 3 fish are used in the assessment then the Prey Fish Water Quality Objective must also be used to determine that the Sport Fish Objective is being met. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027.
Guideline Reference:	Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
Spatial Representation:	Data was collected from 1 station(s) with the station code(s): 713CRNVBD.
Temporal Representation:	Data for this line of evidence were collected between 2004-12-09 and 2004-12-09
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	133324
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Wildlife Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality standard for Mercury. This LOE contains data only for trophic level 4 fish. The concentration of Mercury in fish collected within the same calendar year, for the same trophic level were averaged into a single sample for comparison with the objective. A total of 13 fish were aggregated into 1 annual averages, which consisted of 2 fish species (7 composite(s) of Largemouth Bass each composed of 1 fish per composite, 1 composite(s) of Largemouth Bass each composed of 6 fish per composite).
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Water Quality Control Plan for the Colorado River Basin Region)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The Statewide Sport Fish Water Quality Objective for the protection of Wildlife Habitat comes from the Statewide Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California, and is 0.2 mg/Kg wet weight skinless fillet samples of trophic level 3, or trophic level 4 fish (whichever is highest in the water body) over a one year averaging period. If trophic level 3 fish are used in the assessment then the Prey Fish Water Quality Objective must also be used to determine that the Sport Fish Objective is being met. Trophic levels of applicable fish are defined in, but not limited to those in Attachment C of the Final Regulatory Language document (Appendix A) of State Water Resources Control Board Resolution No. 2017-0027.
Guideline Reference:	Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
Spatial Representation:	Data was collected from 1 station(s) with the station code(s): 713CRNVBD.
Temporal Representation:	Data for this line of evidence were collected between 2004-12-09 and 2004-12-09
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321066
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 172152, Mercury Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321323
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156508	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Merphos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). LOE Removal(s): 29449 ; LOE Replacement(s): 320324
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156508, Merphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320324
Pollutant:	Merphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156508, Merphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128393
Pollutant:	Merphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Merphos.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Merphos, calculated using the IRIS Reference Dose, is 0.2 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.00003 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156483	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methidathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156483, Methidathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351865
Pollutant:	Methidathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Methidathion.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156483, Methidathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128401
Pollutant:	Methidathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Methidathion.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156483, Methidathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320727
Pollutant:	Methidathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156483, Methidathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128400
Pollutant:	Methidathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Methidathion.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156483, Methidathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351863
Pollutant:	Methidathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Methidathion.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156434	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methoxychlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). LOE Removal(s): 7691, 7673; LOE Replacement(s): 319636, 321332
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319636
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128685
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Methoxychlor.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	According to the National Recommended Water Quality Criteria, the maximum (instantaneous) criteria to protect aquatic life from levels of mirex in water is 0.03 ug/l.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35529
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Methoxychlor.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The criterion continuous concentraion for Methoxychlor is 0.3 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7626
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the USEPA criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	USEPA Drinking Water Criteria of 40 ug/l for the protection of drinking water uses (USEPA, 2002).
Guideline Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35530
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Methoxychlor.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Methoxychlor is 30 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128687
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Methoxychlor.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	According to the National Recommended Water Quality Criteria, the maximum (instantaneous) criteria to protect aquatic life from levels of mirex in water is 0.03 ug/l.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321332
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128686
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Methoxychlor.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Methoxychlor is 0.03 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156434, Methoxychlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35552
Pollutant:	Methoxychlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Methoxychlor.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The criterion continuous concentraion for Methoxychlor is 0.3 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156439	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methyl Parathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s). LOE Removal(s): 29448; LOE Replacement(s): 320728
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156439, Methyl Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128229
Pollutant:	Methyl Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Parathion, Methyl.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental phyusiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Department of Fish and Game instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference:	Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156439, Methyl Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35577
Pollutant:	Methyl Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Parathion, Methyl.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Department of Fish and Game instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference:	Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156439, Methyl Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128231
Pollutant:	Methyl Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Parathion, Methyl.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA Health Advisory for lifetime exposure to Parathion, Methyl as a drinking water level is a concentration of 0.001 mg/L
Guideline Reference:	2012 Edition of the Drinking Water Standards and Health Advisories
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156439, Methyl Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35580
Pollutant:	Methyl Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Parathion, Methyl.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Department of Fish and Game instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference:	Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156439, Methyl Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128230
Pollutant:	Methyl Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Parathion, Methyl.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental phyusiological responses in human, plant, animal, or indigenous aquatic life. (Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Department of Fish and Game instantaneous criteria for Methyl Parathion is 0.08 ug/L.
Guideline Reference:	Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156439, Methyl Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320728
Pollutant:	Methyl Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156440	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methyl Tertiary-Butyl Ether (MTBE)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156440, Methyl Tertiary-Butyl Ether (MTBE) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321333
Pollutant:	Methyl Tertiary-Butyl Ether (MTBE)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156440, Methyl Tertiary-Butyl Ether (MTBE) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320203
Pollutant:	Methyl Tertiary-Butyl Ether (MTBE)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156440, Methyl Tertiary-Butyl Ether (MTBE) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35638
Pollutant:	Methyl Tertiary-Butyl Ether (MTBE)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for MTBE.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for MTBE is 0.005 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156435	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methyl bromide
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156435, Methyl bromide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319065
Pollutant:	Methyl bromide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location along this segment of the Colorado River. This sample did not exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 48 ug/l Methyl Bromide, and 5 ug/l Dichloromethane (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. A water sample was collected in 5/2002.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156436	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methyl chloride (Chloromethane)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156436, Methyl chloride (Chloromethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320043
Pollutant:	Methyl chloride (Chloromethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Methyl Chloride, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, or 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156437	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methyl ethyl ketone (2-Butanone)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156437, Methyl ethyl ketone (2-Butanone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319763
Pollutant:	Methyl ethyl ketone (2-Butanone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, or 2-Hexanone for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156438	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methyl isobutyl ketone (Methyl-2-Pentanone)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156438, Methyl isobutyl ketone (Methyl-2-Pentanone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319764
Pollutant:	Methyl isobutyl ketone (Methyl-2-Pentanone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Acetone, Methyl Isobutyl Ketone, Methyl Ethyl Ketone, or 2-Hexanone for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156441	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Methylene bromide (Dibromomethane)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156441, Methylene bromide (Dibromomethane) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320511
Pollutant:	Methylene bromide (Dibromomethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chloroform, Methylene Bromide, Bromochloromethane, Ethylene Dibromide, 1,1,1,2-Tetrachloroethane, 1,2,3,-Trichloropropane, 1,2-Dibromo 3-Chloropropane, 1,3-Dichloropropane, 2,2-Dichloropropane, or 1,1-Dichloropropene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156509	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Mevinphos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156509, Mevinphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320325
Pollutant:	Mevinphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156442	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Mirex
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156442, Mirex Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320892
Pollutant:	Mirex
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156442, Mirex Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35575
Pollutant:	Mirex
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The criterion continuous concentraion for Mirex is 0.001 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156442, Mirex Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128511
Pollutant:	Mirex
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Mirex. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The criterion continuous concentraion for Mirex is 0.001 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156442, Mirex Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128472
Pollutant:	Mirex
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Mirex. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The criterion continuous concentraion for Mirex is 0.001 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156442, Mirex Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45962
Pollutant:	Mirex
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Mirex. One composite (6 fish per composite) were generated from one species: largemouth bass. One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for mirex in fish tissue is 0.28 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Guideline Reference:	Expedited Cancer Potency Values and Proposed Regulatory Levels for Certain Proposition 65 Carcinogens.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156442, Mirex Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35572
Pollutant:	Mirex
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The criterion continuous concentraion for Mirex is 0.001 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156443	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Molinate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156443, Molinate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321184
Pollutant:	Molinate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156443, Molinate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351867
Pollutant:	Molinate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Molinate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for molinate is the USEPA Aquatic Life Benchmark of 105 ug/L for a fish (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156443, Molinate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35615
Pollutant:	Molinate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Molinate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Molinate is 20 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156443, Molinate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128151
Pollutant:	Molinate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Molinate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Molinate is the USEPA Aquatic Life Benchmark of 105 ug/L for a fish (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156443, Molinate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128578
Pollutant:	Molinate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Molinate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Molinate is 0.02 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156443, Molinate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351871
Pollutant:	Molinate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Molinate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for molinate is the USEPA Aquatic Life Benchmark of 105 ug/L for a fish (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156443, Molinate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128575
Pollutant:	Molinate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Molinate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Molinate is the USEPA Aquatic Life Benchmark of 105 ug/L for a fish (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156519	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Naled
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156519, Naled Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320904
Pollutant:	Naled
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156444	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Naphthalene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156444, Naphthalene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319573
Pollutant:	Naphthalene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Naphthalene, 2-Methynaphthalene, or Acenaphthylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156445	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Nickel
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128738
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Nickel.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32939
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the hardness based criteria calculated for nickel.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321067
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319783
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321185
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333671
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Nickel .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for nickel is the probable effect concentration (PEC) of 48.6 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35681
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Nickel.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for nickel is 0.1 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128737
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Nickel.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for nickel is 0.1 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128736
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Nickel.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156445, Nickel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333670
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Nickel .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for nickel is the probable effect concentration (PEC) of 48.6 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	70851	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Nitrate as Nitrate (NO3)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of seven dissolved fraction water samples (collected 2002 - 2005)exceeded the drinking water MCL of 45000 ug/L. Zero of one dissolved fraction (collected 2010) and zero of one total fraction water sample (collected 2013) exceeded the drinking water MCL of 10000 ug/L. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 70851, Nitrate as Nitrate (NO3) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127472
Pollutant:	Nitrogen, Nitrate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Nitrate as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Nitrate as N is 10000 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2013-11-05 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 70851, Nitrate as Nitrate (NO3) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127890
Pollutant:	Nitrogen, Nitrate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Nitrate as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Nitrate as N is 10000 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	103892	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of six samples exceed the California Maximum Contaminant Level. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of six samples exceed the California Maximum Contaminant Level and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 103892, Nitrate/Nitrite (Nitrite + Nitrate as N) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35532
Pollutant:	Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Nitrate/Nitrite (Nitrite + Nitrate as N).
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Nitrate/Nitrite (Nitrite + Nitrate as N) is 10 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	170114	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Nitrogen, Nitrate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170114, Nitrogen, Nitrate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35366
Pollutant:	Nitrate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Nitrate as N.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for nitrate (as N) is 10 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 170114, Nitrogen, Nitrate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321194
Pollutant:	Nitrate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	169696	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Nitrogen, Nitrite
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with updated database requirements.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 169696, Nitrogen, Nitrite Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321193
Pollutant:	Nitrogen, Nitrite
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 169696, Nitrogen, Nitrite Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128311
Pollutant:	Nitrogen, Nitrite
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Nitrite as N.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for nitrite (as N) is 1.0 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 169696, Nitrogen, Nitrite Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35534
Pollutant:	Nitrite as Nitrite NO2
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Nitrite as N.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for nitrite (as N) is 1.0 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156447	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Oxadiazon
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156447, Oxadiazon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351880
Pollutant:	Oxadiazon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxadiazon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Oxadiazon is the USEPA Aquatic Life Benchmark of 0.88 ug/L for a fish (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156447, Oxadiazon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351878
Pollutant:	Oxadiazon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxadiazon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for Oxadiazon is the USEPA Aquatic Life Benchmark of 0.88 ug/L for a fish (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156447, Oxadiazon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320905
Pollutant:	Oxadiazon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlordane, Bolstar, Ciodrin, Dacthal, Demeton s, Dichlorvos, Dimethoate, Disulfoton, Endrin Ketone, Ethoprop, Famphur, Mirex, Naled, or Oxadiazon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156447, Oxadiazon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127424
Pollutant:	Oxadiazon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Oxadiazon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Oxdiazon, calculated using the IRIS Reference Dose, is 35 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.005 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156536	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Oxychlordane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156536, Oxychlordane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320339
Pollutant:	Oxychlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	159272	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Oxygen, Dissolved
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 159272, Oxygen, Dissolved Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335728
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Water Quality Control Plan, Colorado River Basin, Cold Water Habitat Objective, Chapter III, states the following: The dissolved oxygen concentration for cold water habitats shall not be reduced below 8.0 mg/l at any time.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159272, Oxygen, Dissolved Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335706
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Water Quality Control Plan, Colorado River Basin, WARM Water Habitat Objective, Chapter III, states the following: The dissolved oxygen concentration for warm water habitats shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159272, Oxygen, Dissolved Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128158
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Oxygen, Dissolved.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Water Quality Control Plan, Colorado River Basin, WARM Water Habitat Objective, Chapter III, states the following: The dissolved oxygen concentration for cold water habitats shall not be reduced below 5.0 mg/l at any time.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159272, Oxygen, Dissolved Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127724
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Oxygen, Dissolved.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Water Quality Control Plan, Colorado River Basin, Cold Water Habitat Objective, Chapter III, states the following: The dissolved oxygen concentration for cold water habitats shall not be reduced below 8.0 mg/l at any time.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159272, Oxygen, Dissolved Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32312
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Zero of the six samples exceeded the water quality objective for dissolved oxygen.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	From the Colorado River Water Quality Control Plan 'The dissolved Oxygen concentration shall not be reduced below the following minimum levels at any time: for waters designated as COLD-8.0 mg/L.'
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at station 713CRNVBD - Colorado River at Nevada State Line.
Temporal Representation:	The samples were collected during October 2005, May 2006, May 2007, October 2007, April 2008, and October 2008.
Environmental Conditions:
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156454	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	PCBs (Polychlorinated biphenyls)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)., LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156454, PCBs (Polychlorinated biphenyls) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45972
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for PCB, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total PCB was assessed for as follows: PCB aroclors and congeners were summed separately and the sum that yielded the highest value was used for the assessment.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total PCB concentration of 500 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156454, PCBs (Polychlorinated biphenyls) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45971
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for PCB, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total PCB was assessed for as follows: PCB aroclors and congeners were summed separately and the sum that yielded the highest value was used for the assessment.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for polychlorinated biphenyls in fish tissue is 2.6 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156454, PCBs (Polychlorinated biphenyls) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45973
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for PCB, Total. One composite (6 fish per composite) were generated from one species: Largemouth Bass. Total PCB was assessed for as follows: PCB aroclors and congeners were summed separately and the sum that yielded the highest value was used for the assessment.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum total PCB concentration of 500 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156454, PCBs (Polychlorinated biphenyls) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321202
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156454, PCBs (Polychlorinated biphenyls) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128240
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for PCBs (Polychlorinated biphenyls).
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The PCBs criteria for the protection of human health from the consumption of water and organisms is 0.00017 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156454, PCBs (Polychlorinated biphenyls) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32994
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	The method detection limit for all the non-detect samples was greater than the criteria: thus the data was not used in this assessment.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The total PCB criterion for the protection of human health from the consumption of water and organisms is 0.00017 ug/L. This value corresponds to total PCBs, eg., the sum of all congener or isomer or homolog or aroclor analyses (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples were collected on 10/24/2005, 5/2/2006, 5/7/2007, 10/22/2007, 4/21/2008, and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156454, PCBs (Polychlorinated biphenyls) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33413
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 2 samples exceeded the criterion continuous concentration for total PCB. The water body was assessed for the 3 aroclors that were contained within the data set and they include aroclor 1248, aroclor 1254, and aroclor 1260.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The total PCB criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.014 ug/L. This value corresponds to the sum of aroclors 1242, 1254, 1221, 1232, 1248, 1260, and 1016 (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 4/21/2008 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156450	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Parathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156450, Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35536
Pollutant:	Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The criterion continuous concentraion for Parathion, Ethyl is 0.013 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156450, Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127062
Pollutant:	Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Parathion, Ethyl. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The criterion continuous concentraion for Parathion, Ethyl is 0.013 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156450, Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35556
Pollutant:	Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Six samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The criterion continuous concentraion for Parathion, Ethyl is 0.013 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156450, Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127065
Pollutant:	Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Parathion, Ethyl. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The criterion continuous concentraion for Parathion, Ethyl is 0.013 ug/l from the National Recommended Water Quality Criteria.
Guideline Reference:	National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156450, Parathion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320729
Pollutant:	Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	71534	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Perchlorate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of the samples exceed the water quality objectives. Sample sizes for each matrix/fraction/beneficial use/objective combination were less than 16. The sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 71534, Perchlorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128779
Pollutant:	Perchlorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Perchlorate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Perchlorate is 0.006 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 71534, Perchlorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7613
Pollutant:	Perchlorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Level (MCL) of 0.006 mg/l for the protection of human health (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 71534, Perchlorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	129092
Pollutant:	Perchlorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Perchlorate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Perchlorate is 0.006 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 71534, Perchlorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35600
Pollutant:	Perchlorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Perchlorate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Perchlorate is 6 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	170663	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Permethrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170663, Permethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351897
Pollutant:	Permethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of permethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Permethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170663, Permethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351901
Pollutant:	Permethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of permethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Permethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170663, Permethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351904
Pollutant:	Permethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of permethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Permethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170663, Permethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351891
Pollutant:	Permethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The chronic criterion for permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of permethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Water Quality Criteria Report for Permethrin
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156537	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Perylene (Dibenz(de,kl)anthracene)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156537, Perylene (Dibenz(de,kl)anthracene) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320340
Pollutant:	Perylene (Dibenz(de,kl)anthracene)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156453	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Phenanthrene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156453, Phenanthrene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319159
Pollutant:	Phenanthrene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Phenanthrene, or 1-Methylphenanthrene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156488	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Phorate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156488, Phorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351910
Pollutant:	Phorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Phorate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156488, Phorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351908
Pollutant:	Phorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Phorate.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156488, Phorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320341
Pollutant:	Phorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156488, Phorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128981
Pollutant:	Phorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Phorate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156488, Phorate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128980
Pollutant:	Phorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Phorate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156529	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Phosmet
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156529, Phosmet Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320354
Pollutant:	Phosmet
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156529, Phosmet Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351925
Pollutant:	Phosmet
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Phosmet.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for phosmet is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156529, Phosmet Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351920
Pollutant:	Phosmet
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Phosmet.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for phosmet is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156529, Phosmet Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351919
Pollutant:	Phosmet
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Phosmet.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for phosmet is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156529, Phosmet Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351917
Pollutant:	Phosmet
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Phosmet.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for phosmet is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156530	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Phosphamidon
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156530, Phosphamidon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320355
Pollutant:	Phosphamidon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156455	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Prometon (Prometone)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156455, Prometon (Prometone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319360
Pollutant:	Prometon (Prometone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Atroton, Prometon, or Secbumeton for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156455, Prometon (Prometone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127461
Pollutant:	Prometon (Prometone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Prometon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA Health Advisory for 10 day exposure of a 10 kg-Child to Prometon as a drinking water level is a concentration of 0.02 mg/L.
Guideline Reference:	2012 Edition of the Drinking Water Standards and Health Advisories
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156455, Prometon (Prometone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127462
Pollutant:	Prometon (Prometone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Prometon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Prometon is the USEPA Aquatic Life Benchmark of 98 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156455, Prometon (Prometone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351927
Pollutant:	Prometon (Prometone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Prometon.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for prometon (prometone) is the USEPA Aquatic Life Benchmark of 98 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156455, Prometon (Prometone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127460
Pollutant:	Prometon (Prometone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Prometon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Prometon is the USEPA Aquatic Life Benchmark of 98 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156455, Prometon (Prometone) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351931
Pollutant:	Prometon (Prometone)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Prometon.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for prometon (prometone) is the USEPA Aquatic Life Benchmark of 98 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156484	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Prometryn
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156484, Prometryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351942
Pollutant:	Prometryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Prometryn.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Prometryn does not exceed 0.562 ug/L in the water column more than once every three years on average (Bower, et al. 2017).
Guideline Reference:	Water Quality Criteria Report for Prometryn Phase III: Application of the pesticide water quality criteria methodology. Department of Environmental Toxicology. University of California, Davis.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156484, Prometryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351937
Pollutant:	Prometryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Prometryn.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Prometryn does not exceed 0.562 ug/L in the water column more than once every three years on average (Bower, et al. 2017).
Guideline Reference:	Water Quality Criteria Report for Prometryn Phase III: Application of the pesticide water quality criteria methodology. Department of Environmental Toxicology. University of California, Davis.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156484, Prometryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351932
Pollutant:	Prometryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Prometryn.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Prometryn does not exceed 0.562 ug/L in the water column more than once every three years on average (Bower, et al. 2017).
Guideline Reference:	Water Quality Criteria Report for Prometryn Phase III: Application of the pesticide water quality criteria methodology. Department of Environmental Toxicology. University of California, Davis.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156484, Prometryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319345
Pollutant:	Prometryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ametryn, Prometryn, Simetryn, or Terbutryn for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156484, Prometryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351943
Pollutant:	Prometryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Prometryn.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Prometryn does not exceed 0.562 ug/L in the water column more than once every three years on average (Bower, et al. 2017).
Guideline Reference:	Water Quality Criteria Report for Prometryn Phase III: Application of the pesticide water quality criteria methodology. Department of Environmental Toxicology. University of California, Davis.
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156484, Prometryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128224
Pollutant:	Prometryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Prometryn.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Prometryn, calculated using the IRIS Reference Dose, is 28 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.004 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156546	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Propazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156546, Propazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	126965
Pollutant:	Propazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Propazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Propazine is the USEPA Aquatic Life Benchmark of 24.8 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156546, Propazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319142
Pollutant:	Propazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Propazine, or Terbuthylazine for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156546, Propazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351947
Pollutant:	Propazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Propazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for propazine is the USEPA Aquatic Life Benchmark of 24.8 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156546, Propazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351951
Pollutant:	Propazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Propazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for propazine is the USEPA Aquatic Life Benchmark of 24.8 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156546, Propazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127887
Pollutant:	Propazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Propazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Propazine is the USEPA Aquatic Life Benchmark of 24.8 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156456	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Pyrene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156456, Pyrene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321068
Pollutant:	Pyrene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	170666	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Pyrethrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170666, Pyrethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351971
Pollutant:	Pyrethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Pyrethrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for pyrethrin is the USEPA Aquatic Life Benchmark of 0.04 ug/L for freshwater invertebrates (chronic) and is the sum of pyrethrin-1 and pyrethrin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170666, Pyrethrin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351968
Pollutant:	Pyrethrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Pyrethrin.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for pyrethrin is the USEPA Aquatic Life Benchmark of 0.04 ug/L for freshwater invertebrates (chronic) and is the sum of pyrethrin-1 and pyrethrin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	170656	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Pyrethrins
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170656, Pyrethrins Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351981
Pollutant:	Pyrethrins
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Pyrethrins.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for pyrethrins is the USEPA Aquatic Life Benchmark of 0.04 ug/L for an invertebrate (chronic), and is the sum of cinerin-1, cinerin-2, jasmolin-1, jasmolin-2, pyrethrin-1, and pyrethrin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170656, Pyrethrins Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	351985
Pollutant:	Pyrethrins
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Pyrethrins.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for pyrethrins is the USEPA Aquatic Life Benchmark of 0.04 ug/L for an invertebrate (chronic), and is the sum of cinerin-1, cinerin-2, jasmolin-1, jasmolin-2, pyrethrin-1, and pyrethrin-2.
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2013-04-15 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	169365	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Pyrethroids
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 169365, Pyrethroids Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352019
Pollutant:	Pyrethroids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169365, Pyrethroids Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352006
Pollutant:	Pyrethroids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169365, Pyrethroids Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352015
Pollutant:	Pyrethroids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169365, Pyrethroids Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352011
Pollutant:	Pyrethroids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.
Guideline Reference:	Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156457	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Salinity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156457, Salinity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	29463
Pollutant:	Salinity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Three water samples were collected from 5/2002 through 5/2003 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006). No evaluation guideline for Salinity for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Three water samples were collected. The water sample were collected in 5/2002, 10,2002, and 5/2003 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156457, Salinity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321374
Pollutant:	Salinity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected 4/4/2016 to 4/25/2022 from the following Colorado River location: Station Code 713CRNVBD. The samples did not exceed the Basin Plan objective for total dissolved solids of 723 mg/L to protect the CO beneficial use.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Any discharge, excepting discharges from agricultural sources, shall not cause concentration of total dissolved solids (TDS) in surface waters to exceed the following limits of TDS (mg/L): Annual Average 4000, Maximum 4500
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected from the following Colorado River location: Station Code 713CRNVBD.
Temporal Representation:	Four water samples were collected 4/4/2016 to 4/25/2022 from the following Colorado River location: Station Code 713CRNVBD.
Environmental Conditions:
QAPP Information:	SWAMP QAPrP 2009
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156544	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Secbumeton
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156544, Secbumeton Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319500
Pollutant:	Secbumeton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Atroton, Prometon, or Secbumeton for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156458	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Selenium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156458, Selenium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321203
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156458, Selenium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	126937
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Selenium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156458, Selenium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127999
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Selenium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Maximum Contaminant Level for selenium in the Basin Plan is 0.05 mg/L (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156458, Selenium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128000
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Selenium.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156458, Selenium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45982
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Selenium. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The OEHHA Fish Contaminant Goal for selenium in fish tissue is 7.4 ppm. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A background dietary consumption rate of 0.114 mg/day is applied for this micronutrient.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156459	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Silver
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Implementation Action Other than TMDL:	319673 and 320204 result in double counting.
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320204
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319637
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of chemical constituents in excess of the following limits: 10 ug/l Cadmium, 50 ug/l Lead, 4 ug/l Lindane/Hexachlorocyclohexane (HCH), 100 ug/l Methoxychlor, and 50 ug/l Silver (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319784
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32960
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the hardness based criteria calculated for silver.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion maximum concentrations (1-hour average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127402
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Silver.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion maximum concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128719
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Silver.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Secondary MCL for silver is 0.1 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	129016
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Silver.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion maximum concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156459, Silver Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35585
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Silver.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for silver is 0.1 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156460	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Simazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156460, Simazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352020
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Simazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for simazine is the USEPA Aquatic Life Benchmark of 6 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156460, Simazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128199
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Simazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Simazine is 0.004 mg/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156460, Simazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35624
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Simazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Simazine is 4 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156460, Simazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352027
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Simazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for simazine is the USEPA Aquatic Life Benchmark of 6 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156460, Simazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352030
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Simazine.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for simazine is the USEPA Aquatic Life Benchmark of 6 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156460, Simazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352021
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Simazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for simazine is the USEPA Aquatic Life Benchmark of 6 ug/L for a nonvascular plant (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156460, Simazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319073
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Six water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 0.001 mg/l Atrazine, and 0.004 mg/l Simazine (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Six water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October. No sample was collected in October 2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156543	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Simetryn
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156543, Simetryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319346
Pollutant:	Simetryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ametryn, Prometryn, Simetryn, or Terbutryn for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	159274	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Sodium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 159274, Sodium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	336273
Pollutant:	Sodium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Agricultural Supply
Number of Samples:	1
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Sodium.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. At or below the sodium threshold of 69 mg/L, agricultural uses of water should not be limited.
Guideline Reference:	Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2020-10-26 and 2020-10-26
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159274, Sodium Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	336274
Pollutant:	Sodium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Sodium.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	Per the Drinking Water Standards and Health Advisories (USEPA 2012), the health advisory for sodium for individuals on a sodium-restricted diet is 20 mg/l.
Guideline Reference:	2012 Edition of the Drinking Water Standards and Health Advisories
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2020-10-26 and 2020-10-26
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	169565	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Specific Conductivity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	The lines of evidence without flow-weighted data received an insufficient rating because specific conductance/conductivity is associated with salinity which has a flow-weighted site-specific objective in the Basin Plan. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 169565, Specific Conductivity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	336285
Pollutant:	Specific Conductivity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	4
Number of Exceedances:	2
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 2 of 4 samples exceeded the water quality threshold for SpecificConductivity.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The California Secondary MCL for specific conductance is 900 uS/cm (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 169565, Specific Conductivity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35256
Pollutant:	Specific Conductivity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 6 of 6 samples exceed the criterion for Conductivity(Us).
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for specific conductance is 1,600 uS/cm (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 169565, Specific Conductivity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127001
Pollutant:	Specific Conductivity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	2
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 2 of 3 samples exceeded the water quality standard for SpecificConductivity.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Secondary MCL for specific conductance is 900 uS/cm (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 169565, Specific Conductivity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7680
Pollutant:	Specific Conductance
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven measurements were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total measurements, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Level (SMCL) of 1600 umhos for consumer acceptance (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
Spatial Representation:	Measurements were collected near the Califonria Nevada Border.
Temporal Representation:	Seven water quality measurements were collected. Water quality measurements were generally collected biannually from 5/2002 through 5/2005 from the Nevada Border. Measurements were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156461	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Styrene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156461, Styrene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319070
Pollutant:	Styrene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location along this segment of the Colorado River. This sample did not exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 100 ug/l Styrene, and 150 ug/l Trichlorofluoromethane (CFC-11) (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. A water sample was collected in 5/2002.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156462	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Sulfates
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156462, Sulfates Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127198
Pollutant:	Sulfates
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Sulfate.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance of 500 mg/l.
Guideline Reference:	California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156462, Sulfates Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34567
Pollutant:	Sulfates
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	5 of the 6 samples were greater than the Secondary MCLs objective.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Secondary Maximum Contaminant Levels (SMCLs) apply to ambient waters under the Colorado River Basin Region's narrative "Chemical Constituents" objective. The SMCL for Sulfates (SO4) is 500 mg/L.
Objective/Criterion Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at stations 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156462, Sulfates Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320205
Pollutant:	Sulfates
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156531	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Sulfotep
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156531, Sulfotep Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320356
Pollutant:	Sulfotep
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156538	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Tedion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156538, Tedion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320357
Pollutant:	Tedion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	159275	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Temperature, water
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 159275, Temperature, water Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127207
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 1 of 3 samples exceeded the water quality standard for Temperature.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference:	Inland Fishes of California
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159275, Temperature, water Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	336331
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Temperature.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference:	Inland Fishes of California
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159275, Temperature, water Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35407
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Water Temperature.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such alteration in temperature does not adversely affect beneficial uses (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).
Guideline Reference:	Fish introductions in CA: History and impact on native fishes. Davis, CA: University of CA, Davis
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156464	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Terbufos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156464, Terbufos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127036
Pollutant:	Terbufos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Terbufos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Terbufos is the USEPA Aquatic Life Benchmark of 0.03 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156464, Terbufos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319749
Pollutant:	Terbufos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Benzo(g,h,i)Perylene, Benzo(e)Pyrene, Biphenyl, or Terbufos for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156464, Terbufos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127037
Pollutant:	Terbufos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Terbufos. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Terbufos is the USEPA Aquatic Life Benchmark of 0.03 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	Data was collected from 1 station(s) (Station Code(s) 713CRNVBD).
Temporal Representation:	Date for this waterbody was collected over the date range 2010-10-04 to 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156547	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Terbuthylazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156547, Terbuthylazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128306
Pollutant:	Terbuthylazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Terbuthylazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Terbuthylazine is the USEPA Aquatic Life Benchmark of 1800 ug/L for a fish (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156547, Terbuthylazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127218
Pollutant:	Terbuthylazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Terbuthylazine.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Terbuthylazine is the USEPA Aquatic Life Benchmark of 1800 ug/L for a fish (acute).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156547, Terbuthylazine Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319143
Pollutant:	Terbuthylazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Propazine, or Terbuthylazine for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	103058	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Terbutryn
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1, a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the one samples exceed the water quality objective for the "Municipal & Domestic Supply" beneficial use assessed. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the one samples exceed the water quality objective for the "Municipal & Domestic Supply" beneficial use assessed. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 103058, Terbutryn Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127227
Pollutant:	Terbutryn
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Terbutryn.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Terbutryn, calculated using the IRIS Reference Dose, is 7 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.001 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156465	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Tetrachloroethylene/PCE
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156465, Tetrachloroethylene/PCE Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35377
Pollutant:	Tetrachloroethylene/PCE
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Tetrachloroethylene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Tetrachloroethylene criteria for the protection of human health from the consumption of water and organisms is 0.8 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156465, Tetrachloroethylene/PCE Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320287
Pollutant:	Tetrachloroethylene/PCE
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156465, Tetrachloroethylene/PCE Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321212
Pollutant:	Tetrachloroethylene/PCE
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156466	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Tetrachlorvinphos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156466, Tetrachlorvinphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127238
Pollutant:	Tetrachlorvinphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Tetrachlorvinphos.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The USEPA expected safe lifetime exposure limit in drinking water for Tetrachlorvinphos, calculated using the IRIS Reference Dose, is 210 ug/L. This was calculated assuming 70 kg body weight, 2 liters/day water consumption, 20% relative source contribution from drinking water, and 0.03 mg/kg/day as the reference dose.
Guideline Reference:	IRIS Reference Summary (Various Pollutants)
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156466, Tetrachlorvinphos Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320338
Pollutant:	Tetrachlorvinphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Chlorfenvinphos, Cuomaphos, Dicrotophos, Fenchchlorphos, Dyfonate, Leptophos, Merphos, Mevinphos, Tetrachlorvinphos, or Chlorpyrifos, Methyl for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	170662	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Thiobencarb
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320216
Pollutant:	Thiobencarb/Bolero
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352037
Pollutant:	Thiobencarb
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Thiobencarb.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for thiobencarb is the USEPA Aquatic Life Benchmark of 1 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	352039
Pollutant:	Thiobencarb
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed RWB7 Trend data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Thiobencarb.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for thiobencarb is the USEPA Aquatic Life Benchmark of 1 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2005-10-24 and 2008-10-28
Environmental Conditions:
QAPP Information:	Generic SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35386
Pollutant:	Thiobencarb/Bolero
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Thiobencarb.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for thiobencarb is 0.001 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128437
Pollutant:	Thiobencarb
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Thiobencarb.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Thiobencarb is the USEPA Aquatic Life Benchmark of 1 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127251
Pollutant:	Thiobencarb
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Thiobencarb.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Secondary MCL for thiobencarb is 0.001 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128594
Pollutant:	Thiobencarb
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Thiobencarb.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The evaluation guideline for Thiobencarb is the USEPA Aquatic Life Benchmark of 1 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 170662, Thiobencarb Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321213
Pollutant:	Thiobencarb/Bolero
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156539	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Thionazin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156539, Thionazin Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320371
Pollutant:	Thionazin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156532	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Tokuthion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156532, Tokuthion Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320730
Pollutant:	Tokuthion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Ethion, Carbophenothion, Dichlofenthion, Dioxathion, Parathion, Fenitrothion, Fensulfothion, Fenthion, Malathion, Methidathion, Methyl Parathion, or Tokuthion for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156469	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Toluene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156469, Toluene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321079
Pollutant:	Toluene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156469, Toluene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35396
Pollutant:	Toluene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Toluene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Toluene is 150 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156469, Toluene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321222
Pollutant:	Toluene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	159276	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Total Dissolved Solids
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This information is insufficient (since the site-specific objective relies on flow-weighted data) to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 159276, Total Dissolved Solids Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128357
Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	3
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 3 of 3 samples exceeded the water quality standard for Total Dissolved Solids.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	California Secondary Maximum Contaminant Levels (MCLs) for consumer acceptance objective for total dissolved solids is 500 mg/L.
Guideline Reference:	California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159276, Total Dissolved Solids Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	336358
Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Total Dissolved Solids.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	California Secondary Maximum Contaminant Levels (MCLs) for consumer acceptance objective for total dissolved solids is 1000 mg/L.
Guideline Reference:	California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2020-10-26 and 2020-10-26
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	164791	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Toxaphene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 164791, Toxaphene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45985
Pollutant:	Toxaphene
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Toxaphene. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Toxaphene concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 164791, Toxaphene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45984
Pollutant:	Toxaphene
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Toxaphene. One composite (6 fish per composite) were generated from one species: largemouth bass.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	National Academy of Science guidelines (NAS 1972) establish a maximum Toxaphene concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.
Guideline Reference:	National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 164791, Toxaphene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	45983
Pollutant:	Toxaphene
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Fish fillet
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	Fish tissue analysis
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Toxaphene. One composite (6 fish per composite) were generated from one species: largemouth bass. One sample was not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Fish Tissue Study 2004
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The modified OEHHA Fish Contaminant Goal for toxaphene in fish tissue is 4.3 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets.
Guideline Reference:	Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line - 713CRNVBD]
Temporal Representation:	Data was collected on a single day 12/9/2004.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156471	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Trichlorfon
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s).
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156471, Trichlorfon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128569
Pollutant:	Trichlorfon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Trichlorfon.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The acceptable daily intake for Trichlorfon is 26 ug/l. This was calculated for a child assuming 10 kg body weight, 1 liter/day water consumption, 20% relative source contribution from drinking water, and 1.25 mg/kg/day as the reference dose. (National Academy of Sciences Drinking Water and Health, Volume 6, 1986)
Guideline Reference:	National Academy of Sciences Health Advisories document 1986
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156471, Trichlorfon Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320372
Pollutant:	Trichlorfon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156472	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Trichloroethylene/TCE
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156472, Trichloroethylene/TCE Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320078
Pollutant:	Trichloroethylene/TCE
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven samples were taken at 1 location along this segment of the Colorado River. One water sample result could not be used in this assessment because the sample results were non-detect and the detection limit was above the criteria concentration. The six acceptable water quality samples were generally collected and analyzed twice a year from 10/2002 through 5/2005 at 1 location along this segment of the river. Of these total samples, none exceeded the CTR Criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1.2 ug/l Benzene, 4.3 ug/l Bromoform, 0.25 ug/l Carbon Tetrachloride, 0.56 ug/l Dichlorobromomethane, 0.38 ug/l 1,2-Dichloroethane, 0.52 ug/l 1,2-Dichloropropane, 0.44 ug/l Hexachlorobutadiene, 0.80 ug/l Tetrachloroehtylene, 0.6 ug/l 1,1,2-Trichloroethane, and 2.7 ug/l Trichloroethylene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156472, Trichloroethylene/TCE Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35405
Pollutant:	Trichloroethylene/TCE
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Trichloroethylene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The trichloroethylene criteria for the protection of human health from the consumption of water and organisms is 2.7 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156472, Trichloroethylene/TCE Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321223
Pollutant:	Trichloroethylene/TCE
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156473	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Trichlorofluoromethane (CFC-11)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156473, Trichlorofluoromethane (CFC-11) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319071
Pollutant:	Trichlorofluoromethane (CFC-11)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location along this segment of the Colorado River. This sample did not exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 100 ug/l Styrene, and 150 ug/l Trichlorofluoromethane (CFC-11) (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. A water sample was collected in 5/2002.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156540	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Trichloronate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156540, Trichloronate Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320373
Pollutant:	Trichloronate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Oxychlordane, Perylene, Phorate, Phosmet, Phosphamidon, Sulfotep, Tedion, Thionazin, Trichloronate, or Trichlorfon for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	159277	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Turbidity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 159277, Turbidity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7604
Pollutant:	Turbidity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water quality measurements were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total measurements, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Level (SMCL) of 5 NTU for consumer acceptance (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64449 Secondary Drinking Water Standards
Spatial Representation:	Measurements were collected near the California Nevada Border.
Temporal Representation:	Seven water quality measurements were collected. Water quality measurements were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Measurmements were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 159277, Turbidity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128011
Pollutant:	Turbidity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Turbidity.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Basin Plan's \Chemical Constituents\" objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment. "
Guideline Reference:	California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159277, Turbidity Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	336374
Pollutant:	Turbidity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Turbidity.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Basin Plan's 'Chemical Constituents' objective. The Secondary MCL for turbidity is 5 NTU. Calculation of a numeric objective for other beneficial uses requires comparison with upstream or other background data which may not be available as part of the data used for water quality assessment.
Guideline Reference:	California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP

DECISION ID	156475	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Xylenes (total) (mixed)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156475, Xylenes (total) (mixed) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321232
Pollutant:	Xylenes (total) (mixed)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156475, Xylenes (total) (mixed) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33043
Pollutant:	Xylenes (total) (mixed)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Two samples were collected and no samples exceeded the objective.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. California Maximum Containment Levels are incorporated by reference through the basin plan (Colorado River Basin Plan 2006). The California MCL for Xylenes is 1.75 mg/L.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected at Colorado River at Nevada State Line-713CRNVBD.
Temporal Representation:	Samples were collected between 10/24/2005-5/2/2006.
Environmental Conditions:
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156476	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Zinc
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127940
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Zinc.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35408
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Zinc.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	The California Secondary MCL for zinc is 5.0 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127853
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Zinc.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses. (Water Quality Control Plan, Colorado River Basin).
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:	The California Secondary MCL for zinc is 5.0 mg/L (Title 22 California Code of Regulations).
Guideline Reference:	Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127941
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Zinc.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333769
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Zinc .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for zinc is the probable effect concentration (PEC) of 459 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319785
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR hardness dependent criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule Hardness Dependent Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: Lead,Nickel, Silver, and Zinc (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320217
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH SMCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Secondary Maximum Contaminant Levels (SMCLs) for consumer acceptance were used for the following constituents: 0.2 mg/l Aluminum, 500 mg/l Chloride, 1 mg/l Copper, 0.05 mg/l Manganese, 0.005 mg/l MTBE, 0.1 mg/l Silver, 500 mg/l Sulfate, 0.001 mg/l Thiobencarb, and 5 mg/l Zinc (CCR, title 22).
Guideline Reference:	Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	333749
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Sediment
Matrix:	Sediment
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Zinc .
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. There shall be no increase in hazardous chemical concentrations found in bottom sediments or aquatic life. (Water Quality Control Plan, Colorado River Basin)
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:	The evaluation guideline for zinc is the probable effect concentration (PEC) of 459 mg/kg dry weight (MacDonald et al., 2000a).
Guideline Reference:	Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
Spatial Representation:	Data were collected from 1 station(s). Station Code(s): 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Data for this waterbody were collected over the date range 2018-11-12 to 2018-11-12
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 156476, Zinc Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32966
Pollutant:	Zinc, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples exceeded the hardness based criteria calculated for zinc.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) lists criterion continuous concentrations (4-day average) to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	Samples collected between 10/24/2005 and 10/28/2008.
Environmental Conditions:
QAPP Information:	SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156533	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	alpha-Chlordene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156533, alpha-Chlordene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319112
Pollutant:	alpha-Chlordene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of alpha-Chlordene, or gamma-Chlordene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156404	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	alpha-Endosulfan (Endosulfan 1)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128173
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endosulfan I.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule criteria for alpha-endosulfan to protect human health for waters that include the designated use of MUN is 110 ug/L.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321080
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320268
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128171
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endosulfan I.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan I criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for alpha-endosulfan is 0.056 ug/L.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35026
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endosulfan I.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan I criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for alpha-endosulfan is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35021
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endosulfan I.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan I criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for alpha-endosulfan is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35022
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endosulfan I.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule criteria for alpha-endosulfan to protect human health for waters that include the designated use of MUN is 110 ug/L.
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156404, alpha-Endosulfan (Endosulfan 1) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128172
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endosulfan I.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan I criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for alpha-endosulfan is 0.056 ug/L.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156376	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	alpha.-BHC (Benzenehexachloride or alpha-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156376, alpha.-BHC (Benzenehexachloride or alpha-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321081
Pollutant:	alpha.-BHC (Benzenehexachloride or alpha-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156376, alpha.-BHC (Benzenehexachloride or alpha-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127135
Pollutant:	Hexachlorocyclohexane (HCH), alpha
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for HCH, alpha-.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The BHC, alpha criteria for the protection of human health from the consumption of water and organisms is 0.0039 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156376, alpha.-BHC (Benzenehexachloride or alpha-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35151
Pollutant:	Hexachlorocyclohexane (HCH), alpha
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for HCH, alpha.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The BHC, alpha criteria for the protection of human health from the consumption of water and organisms is 0.0039 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan

DECISION ID	156427	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	beta-BHC (Benzenehexachloride or beta-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed.
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156427, beta-BHC (Benzenehexachloride or beta-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35172
Pollutant:	Hexachlorocyclohexane (HCH), beta
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for HCH, beta.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The BHC, beta criteria for the protection of human health from the consumption of water and organisms is 0.014 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156427, beta-BHC (Benzenehexachloride or beta-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321092
Pollutant:	beta-BHC (Benzenehexachloride or beta-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156427, beta-BHC (Benzenehexachloride or beta-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127296
Pollutant:	Hexachlorocyclohexane (HCH), beta
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for HCH, beta-.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The BHC, beta criteria for the protection of human health from the consumption of water and organisms is 0.014 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156449	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	beta-Endosulfan (Endosulfan 2)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35039
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endosulfan II.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule criteria for beta-endosulfan to protect human health for waters that include the designated use of MUN is 110 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	129001
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endosulfan II.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan II criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for beta-endosulfan is 0.056 ug/L.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35043
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endosulfan II.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan II criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for beta-endosulfan is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321093
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320269
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criterion Maximum Concentrations (CMCs) for the protection of freshwater aquatic life uses were used for the following constituents: 3 ug/l Aldrin, 0.22 ug/l alpha-Endosulfan, 340 ug/l Arsenic, 0.22 ug/l beta-Endosulfan, 2.4 ug/l Chlordane 1724 ug/l Chromium, 0.24 ug/l Dieldrin, 0.086 ug/l Endrin, 0.52 ug/l Heptachlor, and 0.52 Heptachlor Epoxide (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128294
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endosulfan II.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan II criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for beta-endosulfan is 0.056 ug/L.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35038
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 6 samples exceed the criterion for Endosulfan II.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Endosulfan II criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for beta-endosulfan is 0.056 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-10/28/2008.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 156449, beta-Endosulfan (Endosulfan 2) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127632
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Endosulfan II.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule criteria for beta-endosulfan to protect human health for waters that include the designated use of MUN is 110 ug/L.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2010-10-04
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156398	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	cis-1,2-Dichloroethylene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156398, cis-1,2-Dichloroethylene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35236
Pollutant:	cis-1,2-Dichloroethylene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dichloroethylene, cis 1,2-.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for Dichloroethylene, cis 1,2- is 6 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156398, cis-1,2-Dichloroethylene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321233
Pollutant:	cis-1,2-Dichloroethylene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156554	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	cis-1,3-Dichloropropene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156554, cis-1,3-Dichloropropene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320057
Pollutant:	cis-1,3-Dichloropropene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Methyl Chloride, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, or 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156501	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	cis-Nonachlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156501, cis-Nonachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319157
Pollutant:	cis-Nonachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of cis-Nonachlor, or trans-Nonachlor for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156468	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	delta-BHC (Benzenehexachloride or delta-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156468, delta-BHC (Benzenehexachloride or delta-HCH) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320456
Pollutant:	delta-BHC (Benzenehexachloride or delta-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156534	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	gama-Chlordene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156534, gama-Chlordene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319113
Pollutant:	gama-Chlordene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of alpha-Chlordene, or gamma-Chlordene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156433	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	m-Dichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156433, m-Dichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321094
Pollutant:	m-Dichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156433, m-Dichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34755
Pollutant:	1, 3 -dichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 3-Dichlorobenzene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The 1, 3-Dichlorobenzene criteria for the protection of human health from the consumption of water and organisms is 400 ug/L (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156552	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	n-Butylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156552, n-Butylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320467
Pollutant:	n-Butylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156490	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	n-Propylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156490, n-Propylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320468
Pollutant:	n-Propylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156446	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	o-Dichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156446, o-Dichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34749
Pollutant:	o-Dichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 2-Dichlorobenzene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for 1, 2-Dichlorobenzene is 600 ug/L (Title 22 of the California Code of Regulations ).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156446, o-Dichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321242
Pollutant:	o-Dichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156446, o-Dichlorobenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321106
Pollutant:	o-Dichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156448	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	o-Xylene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156448, o-Xylene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320469
Pollutant:	o-Xylene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156514	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	p,p'-DDMU
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156514, p,p'-DDMU Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319733
Pollutant:	p,p'-DDMU
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of o,p'-DDD, o,p'-DDE, o,p'-DDT, or p,p'-DDMU for the protection of human, animal or aquatic life in marine waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156451	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	p-Cymene (p-Isopropyltoluene)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156451, p-Cymene (p-Isopropyltoluene) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319555
Pollutant:	p-Cymene (p-Isopropyltoluene)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of 2-Chlorotoluene, 4-Chlorotoluene, or p-Cymene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156452	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	p-Dichlorobenzene (DCB)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Multi-pollutant LOEs were removed and replaced by single-pollutant LOEs to comply with modern database requirements. Detailed information is included in the replacement LOE(s)
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156452, p-Dichlorobenzene (DCB) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321107
Pollutant:	p-Dichlorobenzene (DCB)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CTR criteria (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	California Toxics Rule (CTR) Criteria for the protection of human health when consuming water and organisms from aquatic systems were used for the following constituents: 1200 ug/l Acenaphthene, 0.0093 ug/l alpha-BHC, 110 ug/l alpha-Endosulfan, 9600 ug/l Anthracene, 0.014 ug/l beta-BHC, 110 ug/l beta-Endosulfan, 680 ug/l Chlorobenzene, 1300 ug/l Copper, 2700 ug/l o-Dichlorobenzene, 400 ug/l m-Dichlorobenzene, 400 ug/l p-Dichlorobenzene, 110 ug/l Endosulfan Sulfate, 0.76 ug/l Endrin, 0.76 Endrin Aldehyde, 3100 ug/l Ethylbenzene, 300 ug/l Fluoranthene, 1300 ug/l Fluorene, 0.050 ug/l Mercury, 610 ug/l Nickel, 960 ug/l Pyrene,and 6800 ug/l Toluene (USEPA, 2000).
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156452, p-Dichlorobenzene (DCB) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	321243
Pollutant:	p-Dichlorobenzene (DCB)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water samples were generally collected biannually from 5/2002 through 5/2005 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the CDPH MCL (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:	California Department of Public Health (CDPH) Drinking Water Maximum Contaminant Levels (MCLs) for the protection of human health were used for the following constituents: 1 mg/l Aluminum, 0.05 mg/l Arsenic, 0.0002 mg/l Benzo[a]Pyrene, 0.005 mg/l Cadmium, 0.0001 mg/l Chlordane, 0.05 mg/l Chromium, 0.6 mg/l o-Dichlorobenzene, 0.5 mg/l p-Dichlorobenzene, 0.005 mg/l 1,1-Dichloroethane, 0.006 mg/l 1,1-Dichloroethylene, 0.006 mg/l cis-1,2-Dichloroethylene, 0.01 mg/l 1,2-Dichloroethylene,-trans, 0.005 mg/l 1,2-Dichloropropane, 0.002 mg/l Endrin, 0.3 mg/l Ethylbenzene, 0.00001mg/l Heptachlor, 0.00001 mg/l Heptachlor Epoxide, 0.001 mg/l Hexachlorobenzene, 0.0002 mg/l Lindane/Hexachlorocyclohexane (HCH), 0.002 mg/l Mercury, 0.030 mg/l Methoxychlor, 0.013 mg/l Methly-Tertiary-Butyl Ether (MTBE), 0.02 mg/l Molinate, 0.070 mg/l Chlorobenzene (mono), 0.1 mg/l Nickel, 0.045 mg/l Nitrate, 0.001 mg/l Nitrite as N, 0.0005 mg/l PCBs (total), 0.05 mg/l Selenium, 0.005 mg/l Tetrachloroethylene, 0.07 mg/l Thiobencarb, 0.15 mg/l Toluene, 0.005 mg/l 1,2,4-Trichlorobenzene, 0.2 mg/l 1,1,1-Trichloroethane, 0.005 mg/l 1,1,2-Trichloroethane, 0.005 mg/l Trichloroethylene, and 1.75 mg/l Xylene (CCR, Title 22).
Guideline Reference:	Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Seven water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 156452, p-Dichlorobenzene (DCB) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34788
Pollutant:	1, 4 -dichlorobenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for 1, 4-Dichlorobenzene.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for 1, 4-Dichlorobenzene is 5 ug/L (Title 22 of the California Code of Regulations).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	159273	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127573
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128331
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7705
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Seven water quality measurements were taken at 1 location along this segment of the Colorado River. Two measurements could not be used in this assessment because of equipment failure or lack of proper documentation. The 5 acceptable measurements were collected from 5/2002 through 5/2005 at 1 location. Of these total measurements, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0 (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Measurements were collected near the California Nevada Border.
Temporal Representation:	Seven water quality measurements were collected. Water quality measurements were generally collected and analyzed biannually from 5/2002 through 5/2005 from the Nevada Border. Measurmements were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127578
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Water Contact Recreation
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335816
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Non-Contact Recreation
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335830
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335798
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335807
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Water Contact Recreation
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335865
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Aquaculture
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335936
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Agricultural Supply
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127572
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	32363
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 6 samples were outside the pH range specified in the water quality objective.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0 (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected at station 713CRNVBD - Colorado River at Nevada State Line.
Temporal Representation:	Data were collected during October 2005, May 2006 and 2007, October 2007, April and October 2008.
Environmental Conditions:
QAPP Information:	The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s):	Surface Water Ambient Monitoring Program Quality Assurance Program Plan
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127574
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Aquaculture
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	127570
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Agricultural Supply
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	335984
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 7
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before March 30, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected between the dates of 2016-04-04 and 2022-04-25
Environmental Conditions:
QAPP Information:	General SWAMP QAPrP
QAPP Information Reference(s):	Generic SWAMP QAPrP
Line of Evidence (LOE) for Decision ID 159273, pH Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	128330
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Non-Contact Recreation
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP RWB7 Monitoring data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for pH.
Data Reference:	Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for SWAMP RWB7 Monitoring.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Water Quality Control Plan for the Colorado River Basin Region's water quality objective for all surface waters states the following: Since the regional waters are somewhat alkaline, pH shall range from 6.0-9.0. Discharges shall not cause any changes in pH detrimental to beneficial water uses.
Objective/Criterion Reference:	Water Quality Control Plan for the Colorado River Basin Region (Includes amendments effective on or before January 8, 2019)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site(s) (713CRNVBD)
Temporal Representation:	The samples were collected between the dates of 2010-10-04 and 2013-11-05
Environmental Conditions:
QAPP Information:	Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s):	Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

DECISION ID	156491	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	sec-Butylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156491, sec-Butylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320470
Pollutant:	sec-Butylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156492	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	tert-Butylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156492, tert-Butylbenzene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320481
Pollutant:	tert-Butylbenzene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of delta-BHC, Bromobenzene, 1,2,4-Trimethybenzene, 1,3,5-Trimethylbenzene, Cumene, n-Propylbenzene, n-Butylbenzene, sec-Butylbenzene, tert-Butylbenzene, or o-xylene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156555	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	trans-1,3-Dichloropropene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156555, trans-1,3-Dichloropropene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	320058
Pollutant:	trans-1,3-Dichloropropene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of Methyl Chloride, Dichlorodifluoromethane, cis-1,3-Dichloropropene, trans-1,3-Dichloropropene, or 1,2,3-Trichlorobenzene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	156502	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	trans-Nonachlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available
Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 156502, trans-Nonachlor Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	319158
Pollutant:	trans-Nonachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Five water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006).No evaluation guidelines for the dissolved fractions of cis-Nonachlor, or trans-Nonachlor for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Five water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	77977	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	1, 2-Dibromoethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3.Two water samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy. Thus, staff cannot make a final decision if the water quality objective is met. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 77977, 1, 2-Dibromoethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	34728
Pollutant:	1, 2-Dibromoethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Two samples were collected but were not used in the assessment because the laboratory data reporting limit was above the guideline and therefore the results could not be quantified with the level of certainty required by the Listing Policy.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The California Maximum Contaminant Level for 1, 2-Dibromoethane is 0.05 ug/L (Title 22 of the California Code of Regulations ).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	78379	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Chlorodibromomethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of two water samples exceeded the CTR criteria and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 78379, Chlorodibromomethane Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	35216
Pollutant:	Chlorodibromomethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed SWAMP data for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Dibromochloromethane.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	The Dibromochloromethane criteria is 0.401 ug/L for the protection of human health from consumption of water and organisms (California Toxics Rule, 2000).
Objective/Criterion Reference:	Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data for this line of evidence for Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu) was collected at 1 monitoring site [ Colorado River at Nevada State Line]
Temporal Representation:	Data was collected over the time period 10/24/2005-5/2/2006.
Environmental Conditions:	Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information:	The SWAMP QAPP (2002) was followed.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	77358	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Dibenzothiophene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess Dibenzothiophene consistent with Listing Policy section 3.1. No evaluation guideline for the dissolved fraction of Dibenzothiophene for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. Because there is no appropriate evaluation guideline, staff are unable to make a Listing decision. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. No evaluation guideline for the dissolved fraction of Dibenzothiophene for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 77358, Dibenzothiophene Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	29459
Pollutant:	Dibenzothiophene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 10/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006). No evaluation guideline for the dissolved fraction of Dibenzothiophene for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 10/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	71172	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Enterococcus
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. However, use ratings of LOE Nos. 7610 and 7607 arechanged from fully supporting to sufficient due to insufficient sample size required by the Listing Policy to determine if the water quality objectives are met. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 4 samples exceeded the Basin Plan Enterococcus water quality objective that protects RECI beneficial uses, and none of 4 samples exceeded the Basin Plan Enterococcus water quality objective that protect RECII beneficial uses. These do not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 71172, Enterococcus Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7610
Pollutant:	Enterococcus
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Non-Contact Recreation
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected biannually from 5/2002 through 11/2003 at 1 location along this segment of the Colorado River. Of these total samples, none exceeded the Basin Plan Objective (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan:In the Colorado River the maximum allowable Enterococcus density is 305 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 11/2003 from the Nevada Border. Samples were generally collected in May and October.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)
Line of Evidence (LOE) for Decision ID 71172, Enterococcus Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	7607
Pollutant:	Enterococcus
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Water Contact Recreation
Number of Samples:	4
Number of Exceedances:	1
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected biannually from 5/2002 through 11/2003 at 1 location along this segment of the Colorado River. Of these total samples, 1 exceeded the Basin Plan Objective. The exceedance was found in a sample collected on 11/03/2003 from near the Nevada Border (SWAMP, 2007).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin-Region 7. May 2002-May 2005.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan:In the Colorado River the maximum allowable Enterococcus density is 61 MPN/ 100 ml (CRBRWQCB, 2006).
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 11/2003 from the Nevada Border. Samples were generally collected in May and October. The exceedance was found in a sample collected on 11/03/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	77064	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Hydroxide
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess Hydroxide consistent with Listing Policy section 3.1. No evaluation guideline for the dissolved fraction of Hydroxiden for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. No evaluation guideline for the dissolved fractions of Hydroxide for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 77064, Hydroxide Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	29461
Pollutant:	Hydroxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006). No evaluation guideline for Hydroxide for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	77066	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Pheophytin a
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.7.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess Pheophytin a consistent with Listing Policy section 3.7.1. No evaluation guideline for the dissolved fraction of Pheophytin a for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. Because there is no appropriate evaluation guideline, staff are unable to make a Listing decision. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. No evaluation guideline for the dissolved fraction of Pheophytin a for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 77066, Pheophytin a Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	29462
Pollutant:	Pheophytin a
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	One water sample was collected in 5/2002 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006). No evaluation guideline for Pheophytin a for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	A sample was collected near the California Nevada Border.
Temporal Representation:	One water sample was collected. The water sample was collected in 5/2002 from the Nevada Border.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	77357	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Streptococcus, fecal
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess fecal Streptococcus consistent with Listing Policy section 3.3. No evaluation guideline for the total density of fecal Streptococcus for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. Because there is no appropriate evaluation guideline, staff are unable to make a Listing decision. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. No evaluation guideline for the total density of fecal Streptococcus for the protection of human, animal or aquatic life in fresh waters could be found that meets the requirements of section 6.1.3 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 77357, Streptococcus, fecal Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	29458
Pollutant:	Streptococcus, fecal
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Water Contact Recreation
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006). No evaluation guideline for Streptococcus for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	77063	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Total Petroleum Hydrocarbons as Diesel
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess Total Petroleum Hydrocarbons as Diesel consistent with Listing Policy section 3.1. Total Petroleum Hydrocarbons as Diesel is used to refer to the dissolved fractions of Diesel Range Organics. No evaluation guidelines for the dissolved fractions of Total Petroleum Hydrocarbons as Diesel for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. Because there are no appropriate evaluation guidelines, staff are unable to make a Listing decision. Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification for placing these water segment-pollutant combinations on the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. No evaluation guidelines for the dissolved fractions of Total Petroleum Hydrocarbons as Diesel for the protection of human, animal or aquatic life in fresh waters could be found that meet the requirements of section 6.1.3 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 77063, Total Petroleum Hydrocarbons as Diesel Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	29457
Pollutant:	Total Petroleum Hydrocarbons as Diesel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	Four water samples were collected from 5/2002 through 5/2004 at 1 location in the river (SWAMP, 2006).
Data Reference:	Surface Water Ambient Monitoring Program (SWAMP) Data for organic and inorganic constituents in water and sediment samples collected from water bodies located in the Colorado River Basin- Region 7. May 2002 - May 2004.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Basin Plan: No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses (CRBRWQCB, 2006). No evaluation guidelines for Total Petroleum Hydrocarbons as Diesel, used to refer to the dissolved fractions of Diesel Range Organics (dro), for the protection of human, animal or aquatic life in fresh waters could be found that met the requirements of Section 6.1.3 of the Listing Policy.
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Samples were collected near the California Nevada Border.
Temporal Representation:	Four water samples were collected. Water samples were generally collected and analyzed biannually from 5/2002 through 5/2004 from the Nevada Border. Samples were usually collected in May and October. A sample was not collected in 11/2003.
Environmental Conditions:
QAPP Information:	The sampling and analysis portions of this study were conducted in accordance with the SWAMP Quality Assurance Management Plan (QAMP) (Puckett, 2002).
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

DECISION ID	78645	Region 7
Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)

Pollutant:	Total Trihalomethane (TTHM)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of two water samples exceeded the California MCL and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Decision Recommendation:	This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
State Board Review of Regional Board Conclusion and Recommendation:
State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 78645, Total Trihalomethane (TTHM) Region 7      Colorado River and Associated Lakes and Reservoirs (California-Nevada border to Lake Havasu)
LOE ID:	33040
Pollutant:	Total Trihalomethane (TTHM)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	None of the 2 samples exceeded the guidelines.
Data Reference:	RWB7 Trend Monitoring CY2005 CY2006 CY2007 CY2008
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	No individual chemical or combination of chemicals shall be present in concentrations that adversely affect beneficial uses.(Water Quality Control Plan for the Colorado River Basin, 2006). California primary Maximum Contaminant Levels (MCLs) apply to ambient waters under the "Chemical Constituents" objective. The primary MCL for Total Trihalomethanes is 0.080 mg/L (80 ug/L).
Objective/Criterion Reference:	Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22
Objective/Criterion Reference:	Water Quality Control Plan Colorado River Basin, with amendments adopted through June 2006
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at station 713CRNVBD (Colorado River at Nevada State Line).
Temporal Representation:	The samples were collected on 10/24/2005, and 5/2/2006.
Environmental Conditions:
QAPP Information:	SWAMP (2002) procedure.
QAPP Information Reference(s):	Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)