Final California 2024 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 8 - Santa Ana Region

Water Body Name:	Santa Ana River, Reach 4
Water Body ID:	CAR8012700019990211142130
Water Body Type:	River & Stream

DECISION ID	149175	Region 8
Santa Ana River, Reach 4

Pollutant:	Indicator Bacteria
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)(2018)
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant
Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under sections 4.2 and 4.3 of the Listing Policy. Under these sections a single line of evidence is necessary to assess listing status. The State Water Board’s Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (the “ISWEBE Plan”) contains two bacteria water quality objectives applicable to the REC-1 beneficial use, which were adopted on August 7, 2018. Because the salinity level of this waterbody is equal to or less than 1 part per thousand 95 percent or more of the time, the E. coli bacteria objective applies. Therefore, this waterbody is being considered for removal from the CWA section 303(d) List under section 4.3 of the Listing Policy using the E. coli objective. Five (5) lines of evidence are available in the administrative record to assess this pollutant for the REC-1 beneficial use. Seven (7) of 34 samples exceed the 6-week E.coli Geomean 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 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. Seven (7) of 34 samples exceed the 6-week E.coli Geomean objective and this exceeds the allowable frequency in Table 4.2 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. In accordance with section 6.1.5.3 of the Listing Policy, data should be representative of the critical timing that the pollutant is expected to impact the waterbody. Indicator bacteria (total coliform, fecal coliform, E. coli, enterococci) populations may fluctuate substantially on a daily, seasonal, or yearly basis. Lacking constant inputs, they do not persist in the environment for a long period and effects are of relatively short duration. As a result, the historic levels of indicator bacteria in the waterbody may be a poor indicator of current risks to human health, particularly when more recent data are available to sufficiently assess the water quality standard. Unrepresentative data may result in incorrectly placing or not placing a water body segment on the list, which could result in the unnecessary expenditure of public resources or failure to address a human health risk. The historic line of evidence was evaluated pursuant to these considerations and was not used to assess water quality standards attainment because it does not meet the temporal representation requirements of section 6.1.5.3 of the Listing Policy. This historic line of evidence is 1 LOE for Pathogens (4432) and will be retired. For E.coli data, Listing Policy sections 3.3 and 4.3 instructs to use the binomial distribution table in sections 3.2 and 4.2, as applicable. To use the binomial table that uses a four percent exceedance frequency, the data must be collected from coastal beaches or inland surface waters from April 1 through October 31 only, and where collected from inland waters from April 1 through October 31 only, bacterial measurements must be indicative of human fecal matter, and there is substantial human contact in the waterbody. 303(d) listing decisions made prior to 2006 were not held in an assessment database.
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:	303(d) listing decisions made prior to 2006 were not held in an assessment database.
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 149175, Indicator Bacteria Region 8      Santa Ana River, Reach 4
LOE ID:	300905
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	STV
Beneficial Use:	Water Contact Recreation
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	PATHOGEN MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Middle Santa Ana River TMDL Monitoring Project data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference:	Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
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): P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the days of 2019-07-31 and 2019-09-04 .
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 149175, Indicator Bacteria Region 8      Santa Ana River, Reach 4
LOE ID:	301015
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	STV
Beneficial Use:	Water Contact Recreation
Number of Samples:	15
Number of Exceedances:	1
Data and Information Type:	PATHOGEN MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Regional Monitoring Program data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 1 of the 15 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference:	Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
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): P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the days of 2016-08-25 and 2020-09-24 .
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 149175, Indicator Bacteria Region 8      Santa Ana River, Reach 4
LOE ID:	300921
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	STV
Beneficial Use:	Water Contact Recreation
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PATHOGEN MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 14 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).
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): 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the days of 2013-07-10 and 2020-06-03 .
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 149175, Indicator Bacteria Region 8      Santa Ana River, Reach 4
LOE ID:	300914
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	GeoMean
Beneficial Use:	Water Contact Recreation
Number of Samples:	32
Number of Exceedances:	7
Data and Information Type:	PATHOGEN MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Regional Monitoring Program data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 7 of the 32 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.
Data Reference:	Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The bacteria water quality objective to protect the REC-1 beneficial use for waters where the salinity is equal to or less than 1 part per thousand 95 percent or more of the time applies a rolling six-week geometric mean of E. coli, not to exceed 100 cfu/100 mL (ISWEBE 2018).
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): P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the days of 2016-08-25 and 2020-09-24 .
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 149175, Indicator Bacteria Region 8      Santa Ana River, Reach 4
LOE ID:	300885
Pollutant:	Escherichia coli (E. coli)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	GeoMean
Beneficial Use:	Water Contact Recreation
Number of Samples:	2
Number of Exceedances:	0
Data and Information Type:	PATHOGEN MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Middle Santa Ana River TMDL Monitoring Project data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 2 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.
Data Reference:	Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The bacteria water quality objective to protect the REC-1 beneficial use for waters where the salinity is equal to or less than 1 part per thousand 95 percent or more of the time applies a rolling six-week geometric mean of E. coli, not to exceed 100 cfu/100 mL (ISWEBE 2018).
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): P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the days of 2019-07-31 and 2019-09-04 .
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program

DECISION ID	132907	Region 8
Santa Ana River, Reach 4

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:	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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132907, 1,1,2-Trichloroethane Region 8      Santa Ana River, Reach 4
LOE ID:	238079
Pollutant:	1,1,2-Trichloroethane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Trichloroethane, 1,1,2-.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA National Recommended Water Quality Criteria (Gold Book) for freshwater aquatic life protection, chronic Lowest Observed Effect Level is 9,400 ug/L.
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-06-10
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132896	Region 8
Santa Ana River, Reach 4

Pollutant:	Acrolein
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 132896, Acrolein Region 8      Santa Ana River, Reach 4
LOE ID:	234911
Pollutant:	Acrolein
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality threshold for Acrolein. Although a total of 2 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA recommended acrolein criterion for the protection of aquatic life in freshwater is 3 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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2014-06-04
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132900	Region 8
Santa Ana River, Reach 4

Pollutant:	Aldrin
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132900, Aldrin Region 8      Santa Ana River, Reach 4
LOE ID:	234913
Pollutant:	Aldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	10
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality threshold for Aldrin.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The aldrin criterion maximum concentration (expressed as a 1-day average) to protect aquatic life in freshwater is 1.5 ug/L. The criterion of 3 ug/L provided in the California Toxics Rule is an instantaneous maximum concentration and was divided by 2 in order to better represent a criterion maximum concentration (CMC) value as specified in footnote (g) of Table (b)(1) of the 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132902	Region 8
Santa Ana River, Reach 4

Pollutant:	Alkalinity as CaCO3
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132902, Alkalinity as CaCO3 Region 8      Santa Ana River, Reach 4
LOE ID:	234942
Pollutant:	Alkalinity as CaCO3
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 Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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: SAR-5 (Santa Ana River upstream of Mission Blvd.).
Temporal Representation:	The samples were collected between the dates of 2019-07-30 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
Line of Evidence (LOE) for Decision ID 132902, Alkalinity as CaCO3 Region 8      Santa Ana River, Reach 4
LOE ID:	234943
Pollutant:	Alkalinity as CaCO3
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 Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Alkalinity as CaCO3.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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: SAR-2a (Santa Ana River upstream of RIX Outfall).
Temporal Representation:	The samples were collected between the dates of 2019-07-30 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

DECISION ID	150623	Region 8
Santa Ana River, Reach 4

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:	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 150623, Ammonia Region 8      Santa Ana River, Reach 4
LOE ID:	240222
Pollutant:	Ammonia (Unionized)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	10
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Ammonia as N, Unionized.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Site-Specific Objective: To prevent chronic toxicity to aquatic life in the Santa Ana River, Reaches 2, 3, and 4, Chino Creek, Mill Creek (Prado Area), Temescal Creek and San Timoteo Creek, discharges to these waterbodies shall not cause the concentration of un-ionized ammonia (as nitrogen) to exceed 0.098 mg/L (NH3-N) as a 4-day average.
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857)
Temporal Representation:	The samples were collected between the dates of 2014-06-04 and 2020-06-03
Environmental Conditions:
QAPP Information:	RC NPDES MS4 MP
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132846	Region 8
Santa Ana River, Reach 4

Pollutant:	Antimony
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132846, Antimony Region 8      Santa Ana River, Reach 4
LOE ID:	235380
Pollutant:	Antimony
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Antimony.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA Quality Criteria for Water (Gold Book) states that for antimony toxicity to algae occurs at 610 ug/l. (USEPA, 1986)
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132846, Antimony Region 8      Santa Ana River, Reach 4
LOE ID:	235382
Pollutant:	Antimony
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Antimony.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA Quality Criteria for Water (Gold Book) states that for antimony toxicity to algae occurs at 610 ug/l. (USEPA, 1986)
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132847	Region 8
Santa Ana River, Reach 4

Pollutant:	Arsenic
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132847, Arsenic Region 8      Santa Ana River, Reach 4
LOE ID:	235443
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Arsenic.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 150 ug/L. The conversion factor used to convert the total fraction criterion for arsenic to dissolved fraction criterion is 1. Therefore all data was considered to be representative of the dissolved fraction. (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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	151777	Region 8
Santa Ana River, Reach 4

Pollutant:	Atrazine
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 151777, Atrazine Region 8      Santa Ana River, Reach 4
LOE ID:	307401
Pollutant:	Atrazine
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Atrazine. Although a total of 4 samples were collected, 4 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	USEPA National Recommended Ambient Water Quality Criteria Aquatic Life Protection Instantaneous Max for atrazine: 1 ug/l.
Guideline Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2015-06-17
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132866	Region 8
Santa Ana River, Reach 4

Pollutant:	Azinphos-methyl (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 132866, Azinphos-methyl (Guthion) Region 8      Santa Ana River, Reach 4
LOE ID:	235566
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 Santa Ana Region data for Santa Ana River, Reach 4 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 13 samples were collected, 13 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA National Recommended Water Quality Criteria for azinphos methyl for freshwater aquatic life protection is 0.01 ug/l (instantaneous maximum)
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	153774	Region 8
Santa Ana River, Reach 4

Pollutant:	Benthic Community Effects
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:	Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects. One line(s) of evidence evaluating benthic-macroinvertebrate bioassessment data is/are available in the administrative record to assess this indicator. One of four benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. However, a minimum of two benthic-macroinvertebrate samples are needed to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing Benthic Community Effects in this waterbody segment 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. One of 4 benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. The available information is insufficient to determine whether the waterbody/pollutant combination should be placed on the 303(d) List of impaired waters at this time. 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:	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 153774, Benthic Community Effects Region 8      Santa Ana River, Reach 4
LOE ID:	314362
Pollutant:	Benthic-Macroinvertebrate Bioassessments
LOE Subgroup:	Population/Community Degradation
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Benthic macroinvertebrate surveys
Data Used to Assess Water Quality:	Water Board staff assessed data for SMC10685 to determine beneficial use support and the results are as follows: 0 of 1 samples exceeded the threshold. CSCI scores were from 0.81450708 to 0.81450708.
Data Reference:	California Stream Condition Index (CSCI) Scores for the 2024 Integrated Report for Region 8.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Inland surface water communities and populations, including vertebrate, invertebrate, and plant species, shall not be degraded as a result of the discharge of waste. Degradation is damage to an aquatic community or population with the result that balanced community no longer exists. The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rehn, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.
Guideline Reference:	Bioassessment in complex environments: designing an index for consistent meaning in different settings
Spatial Representation:	Samples were collected from station SMC10685.
Temporal Representation:	Samples were collected from 7/1/2010 to 7/1/2010.
Environmental Conditions:
QAPP Information:	Data collected following SWAMP QA protocols.
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
Line of Evidence (LOE) for Decision ID 153774, Benthic Community Effects Region 8      Santa Ana River, Reach 4
LOE ID:	314253
Pollutant:	Benthic-Macroinvertebrate Bioassessments
LOE Subgroup:	Population/Community Degradation
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	1
Number of Exceedances:	0
Data and Information Type:	Benthic macroinvertebrate surveys
Data Used to Assess Water Quality:	Water Board staff assessed data for 801M16976 to determine beneficial use support and the results are as follows: 0 of 1 samples exceeded the threshold. CSCI scores were from 0.80475757 to 0.80475757.
Data Reference:	California Stream Condition Index (CSCI) Scores for the 2024 Integrated Report for Region 8.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Inland surface water communities and populations, including vertebrate, invertebrate, and plant species, shall not be degraded as a result of the discharge of waste. Degradation is damage to an aquatic community or population with the result that balanced community no longer exists. The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rehn, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.
Guideline Reference:	Bioassessment in complex environments: designing an index for consistent meaning in different settings
Spatial Representation:	Samples were collected from station 801M16976.
Temporal Representation:	Samples were collected from 6/6/2018 to 6/6/2018.
Environmental Conditions:
QAPP Information:	Data collected following SWAMP QA protocols.
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
Line of Evidence (LOE) for Decision ID 153774, Benthic Community Effects Region 8      Santa Ana River, Reach 4
LOE ID:	314320
Pollutant:	Benthic-Macroinvertebrate Bioassessments
LOE Subgroup:	Population/Community Degradation
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	1
Data and Information Type:	Benthic macroinvertebrate surveys
Data Used to Assess Water Quality:	Water Board staff assessed data for 801SARH60 to determine beneficial use support and the results are as follows: 1 of 2 samples exceeded the threshold. CSCI scores were from 0.591346203 to 0.675883422.
Data Reference:	California Stream Condition Index (CSCI) Scores for the 2024 Integrated Report for Region 8.
SWAMP Data:	SWAMP
Water Quality Objective/Criterion:	Inland surface water communities and populations, including vertebrate, invertebrate, and plant species, shall not be degraded as a result of the discharge of waste. Degradation is damage to an aquatic community or population with the result that balanced community no longer exists. The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses.
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rehn, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.
Guideline Reference:	Bioassessment in complex environments: designing an index for consistent meaning in different settings
Spatial Representation:	Samples were collected from station 801SARH60.
Temporal Representation:	Samples were collected from 10/11/2005 to 10/12/2005.
Environmental Conditions:
QAPP Information:	Data collected following SWAMP QA protocols.
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

DECISION ID	132849	Region 8
Santa Ana River, Reach 4

Pollutant:	Beryllium
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132849, Beryllium Region 8      Santa Ana River, Reach 4
LOE ID:	235549
Pollutant:	Beryllium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Beryllium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The Gold Book states that beryllium chronic toxicity to freshwater aquatic life occur at concentrations as low as 5.3 ug/L.
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132849, Beryllium Region 8      Santa Ana River, Reach 4
LOE ID:	235719
Pollutant:	Beryllium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Beryllium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The Gold Book states that beryllium chronic toxicity to freshwater aquatic life occur at concentrations as low as 5.3 ug/L.
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132850	Region 8
Santa Ana River, Reach 4

Pollutant:	Boron
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132850, Boron Region 8      Santa Ana River, Reach 4
LOE ID:	235743
Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Groundwater Recharge
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Boron.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Boron concentrations shall not exceed 0.75 mg/L in inland surface waters of the region as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132850, Boron Region 8      Santa Ana River, Reach 4
LOE ID:	235742
Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Groundwater Recharge
Number of Samples:	13
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 13 samples exceeded the water quality threshold for Boron.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Boron concentrations shall not exceed 0.75 mg/L in inland surface waters of the region as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132851	Region 8
Santa Ana River, Reach 4

Pollutant:	Cadmium
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132851, Cadmium Region 8      Santa Ana River, Reach 4
LOE ID:	239988
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality standard for Cadmium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Site-Specific Objective: The Santa Ana River Basin Water Quality Control Plan lists site specific objectives (SSOs) to protect aquatic life in freshwater. The SSOs in freshwater are hardness dependent for each sample and vary based on the ambient hardness during sampling. Sections 4-11 through 4-13 in the Santa Ana River Basin Water Quality Control Plan contain the hardness dependent formula for the metals SSOs.
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857)
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	RC NPDES MS4 MP
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132852	Region 8
Santa Ana River, Reach 4

Pollutant:	Chlordane
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132852, Chlordane Region 8      Santa Ana River, Reach 4
LOE ID:	238027
Pollutant:	Chlordane
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 7 samples exceeded the water quality threshold for Total Chlordane. Although a total of 11 samples were collected, 4 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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:	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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2014-07-23 to 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132853	Region 8
Santa Ana River, Reach 4

Pollutant:	Chlorpyrifos
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 132853, Chlorpyrifos Region 8      Santa Ana River, Reach 4
LOE ID:	235876
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 Santa Ana Region data for Santa Ana River, Reach 4 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 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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
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:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132906	Region 8
Santa Ana River, Reach 4

Pollutant:	Chlorpyrifos, methyl
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132906, Chlorpyrifos, methyl Region 8      Santa Ana River, Reach 4
LOE ID:	235915
Pollutant:	Chlorpyrifos, methyl
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Chlorpyrifos Methyl. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132908	Region 8
Santa Ana River, Reach 4

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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132908, Chromium Region 8      Santa Ana River, Reach 4
LOE ID:	235982
Pollutant:	Chromium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Chromium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved chromium (III) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is is hardness dependent as described in Table 1 of paragraph (b)(1). The value calculated when using a default hardness of 100 mg/L is 180 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:	The dissolved chromium (III) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is is hardness dependent as described in Table 1 of paragraph (b)(1). The value calculated when using a default hardness of 100 mg/L is 180 ug/L (California Toxics Rule, 2000).
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132854	Region 8
Santa Ana River, Reach 4

Pollutant:	Chromium, hexavalent
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132854, Chromium, hexavalent Region 8      Santa Ana River, Reach 4
LOE ID:	235843
Pollutant:	Chromium, hexavalent
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Chromium VI.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved chromium (VI) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 11 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132855	Region 8
Santa Ana River, Reach 4

Pollutant:	Chromium, trivalent
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 132855, Chromium, trivalent Region 8      Santa Ana River, Reach 4
LOE ID:	236149
Pollutant:	Chromium, trivalent
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	12
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality threshold for Chromium III.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved chromium (III) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 180 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2014-07-23 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132856	Region 8
Santa Ana River, Reach 4

Pollutant:	Copper
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132856, Copper Region 8      Santa Ana River, Reach 4
LOE ID:	235828
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Copper.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved copper criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 9 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132910	Region 8
Santa Ana River, Reach 4

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:	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 132910, Coumaphos Region 8      Santa Ana River, Reach 4
LOE ID:	235871
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 Santa Ana Region data for Santa Ana River, Reach 4 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 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132857	Region 8
Santa Ana River, Reach 4

Pollutant:	Cyanide
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132857, Cyanide Region 8      Santa Ana River, Reach 4
LOE ID:	235872
Pollutant:	Cyanide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 1 of 14 samples exceeded the water quality threshold for Cyanide.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The cyanide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5.2 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132909	Region 8
Santa Ana River, Reach 4

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:	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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132909, Demeton Region 8      Santa Ana River, Reach 4
LOE ID:	236188
Pollutant:	Demeton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Demeton, Total. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA National Recommended Water Quality criterion for demeton for freshwater aquatic life protection is 0.1 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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132859	Region 8
Santa Ana River, Reach 4

Pollutant:	Diazinon
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132859, Diazinon Region 8      Santa Ana River, Reach 4
LOE ID:	236228
Pollutant:	Diazinon
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Diazinon. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The freshwater chronic value for diazinon is 0.10 ug/L (4 day average)(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
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:	The samples were collected at 1 monitoring site (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132860	Region 8
Santa Ana River, Reach 4

Pollutant:	Dichlorvos
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 132860, Dichlorvos Region 8      Santa Ana River, Reach 4
LOE ID:	236242
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 Santa Ana Region data for Santa Ana River, Reach 4 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 13 samples were collected, 13 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132861	Region 8
Santa Ana River, Reach 4

Pollutant:	Dieldrin
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132861, Dieldrin Region 8      Santa Ana River, Reach 4
LOE ID:	236244
Pollutant:	Dieldrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	12
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality threshold for Dieldrin.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132897	Region 8
Santa Ana River, Reach 4

Pollutant:	Dimethoate
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132897, Dimethoate Region 8      Santa Ana River, Reach 4
LOE ID:	236260
Pollutant:	Dimethoate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Dimethoate. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	151778	Region 8
Santa Ana River, Reach 4

Pollutant:	Disulfoton
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 151778, Disulfoton Region 8      Santa Ana River, Reach 4
LOE ID:	307405
Pollutant:	Disulfoton
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Disulfoton. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	USEPA National Recommended Water Quality Criteria Aquatic Life Protection Instantaneous Max for disulfoton: 0.05 ppb.
Guideline Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132863	Region 8
Santa Ana River, Reach 4

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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132863, Dyfonate (Fonofos or Fonophos) Region 8      Santa Ana River, Reach 4
LOE ID:	236248
Pollutant:	Dyfonate (Fonofos or Fonophos)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Fonofos. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The evaluation guideline for fonofos is the maximum acceptable toxicant concentration (MATC) of 0.45 ug/L. The MATC is calculated as the geometric mean of the lowest observed effect concentration (LOEC) of 0.64 ug/L and the no observed effect concentration (NOEC) of 0.31 ug/L, as determined in a 21 day toxicity study with the water flea, Daphnia magna. Threshold values (LOEC and NOEC) are from USEPA Office of Pesticide Programs Ecotoxicity database.
Guideline Reference:	OPP Pesticide Ecotoxicity Database.
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132864	Region 8
Santa Ana River, Reach 4

Pollutant:	Endosulfan sulfate
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132864, Endosulfan sulfate Region 8      Santa Ana River, Reach 4
LOE ID:	236299
Pollutant:	Endosulfan sulfate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	11
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 11 samples exceeded the water quality threshold for Endosulfan Sulfate.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA National Recommended Water Quality Criteria toxicity threshold for endosulfan sulfate for freshwater aquatic life protection is 0.056 ug/l (24 hour 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132865	Region 8
Santa Ana River, Reach 4

Pollutant:	Endrin
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132865, Endrin Region 8      Santa Ana River, Reach 4
LOE ID:	236314
Pollutant:	Endrin
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	11
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 11 samples exceeded the water quality threshold for Endrin.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132894	Region 8
Santa Ana River, Reach 4

Pollutant:	Ethion
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 132894, Ethion Region 8      Santa Ana River, Reach 4
LOE ID:	236408
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 Santa Ana Region data for Santa Ana River, Reach 4 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 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132898	Region 8
Santa Ana River, Reach 4

Pollutant:	Ethoprop
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132898, Ethoprop Region 8      Santa Ana River, Reach 4
LOE ID:	236410
Pollutant:	Ethoprop
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Ethoprop. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132895	Region 8
Santa Ana River, Reach 4

Pollutant:	Ethyl p-nitrophenyl (EPN)
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132895, Ethyl p-nitrophenyl (EPN) Region 8      Santa Ana River, Reach 4
LOE ID:	236317
Pollutant:	Ethyl p-nitrophenyl (EPN)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for EPN.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The evaluation guideline for EPN is the LC50 of 6.8 ug/L for Gammarus fasciatus (Scud) (USEPA Office of Pesticide Programs Ecotoxicity database).
Guideline Reference:	OPP Pesticide Ecotoxicity Database.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2015-06-17
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132903	Region 8
Santa Ana River, Reach 4

Pollutant:	Fenitrothion
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132903, Fenitrothion Region 8      Santa Ana River, Reach 4
LOE ID:	236428
Pollutant:	Fenitrothion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Fenitrothion. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132904	Region 8
Santa Ana River, Reach 4

Pollutant:	Fenthion
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 132904, Fenthion Region 8      Santa Ana River, Reach 4
LOE ID:	236229
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 Santa Ana Region data for Santa Ana River, Reach 4 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 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132867	Region 8
Santa Ana River, Reach 4

Pollutant:	Heptachlor
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132867, Heptachlor Region 8      Santa Ana River, Reach 4
LOE ID:	236267
Pollutant:	Heptachlor
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 5 samples exceeded the water quality threshold for Heptachlor. Although a total of 11 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132868	Region 8
Santa Ana River, Reach 4

Pollutant:	Heptachlor epoxide
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132868, Heptachlor epoxide Region 8      Santa Ana River, Reach 4
LOE ID:	236268
Pollutant:	Heptachlor epoxide
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	5
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 5 samples exceeded the water quality threshold for Heptachlor Epoxide. Although a total of 11 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132869	Region 8
Santa Ana River, Reach 4

Pollutant:	Iron
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132869, Iron Region 8      Santa Ana River, Reach 4
LOE ID:	236286
Pollutant:	Iron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Iron.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	National Recommended Water Quality Criteria Continuous Concentrations are intended protect freshwater aquatic organisms from chronic exposures and are expressed as 4-day average concentrations. The evaluation guideline for Iron is 1,000 ug/L.
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132869, Iron Region 8      Santa Ana River, Reach 4
LOE ID:	236287
Pollutant:	Iron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Iron.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	National Recommended Water Quality Criteria Continuous Concentrations are intended protect freshwater aquatic organisms from chronic exposures and are expressed as 4-day average concentrations. The evaluation guideline for Iron is 1,000 ug/L.
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132870	Region 8
Santa Ana River, Reach 4

Pollutant:	Lead
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132870, Lead Region 8      Santa Ana River, Reach 4
LOE ID:	239990
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality standard for Lead.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Site-Specific Objective: The Santa Ana River Basin Water Quality Control Plan lists site specific objectives (SSOs) to protect aquatic life in freshwater. The SSOs in freshwater are hardness dependent for each sample and vary based on the ambient hardness during sampling. Sections 4-11 through 4-13 in the Santa Ana River Basin Water Quality Control Plan contain the hardness dependent formula for the metals SSOs.
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857)
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	RC NPDES MS4 MP
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132871	Region 8
Santa Ana River, Reach 4

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:	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 132871, Lindane/gamma Hexachlorocyclohexane (gamma-HCH) Region 8      Santa Ana River, Reach 4
LOE ID:	236264
Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	12
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality threshold for HCH, gamma-.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The gamma-BHC (Lindane, gamma-HCH) 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	154747	Region 8
Santa Ana River, Reach 4

Pollutant:	Malathion
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 154747, Malathion Region 8      Santa Ana River, Reach 4
LOE ID:	316262
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 Santa Ana Region data for Santa Ana River, Reach 4 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 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	Aquatic life should not be affected unacceptably if the 4-day average concentration of Malathion does not exceed 0.028 ug/L more than once every three years on the average (UC Davis Aquatic Life Criterion).
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	149107	Region 8
Santa Ana River, Reach 4

Pollutant:	Mercury
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 149107, Mercury Region 8      Santa Ana River, Reach 4
LOE ID:	236758
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	13
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 13 samples exceeded the water quality threshold for Mercury.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 149107, Mercury Region 8      Santa Ana River, Reach 4
LOE ID:	236695
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Mercury.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	National Recommended Water Quality Criteria Continuous Concentration (4-day average concentrations) for freshwater aquatic organisms exposure to total mercury is 0.77 ug/L.
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132872	Region 8
Santa Ana River, Reach 4

Pollutant:	Methyl Parathion
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132872, Methyl Parathion Region 8      Santa Ana River, Reach 4
LOE ID:	237223
Pollutant:	Methyl Parathion
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Parathion, Methyl. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The California Department of Fish and Game instantaneous aquatic life criterion 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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132901	Region 8
Santa Ana River, Reach 4

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 132901, Naled Region 8      Santa Ana River, Reach 4
LOE ID:	236508
Pollutant:	Naled
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Naled. Although a total of 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The evaluation guideline for naled is the USEPA Aquatic Life Benchmark of 0.01 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132873	Region 8
Santa Ana River, Reach 4

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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132873, Naphthalene Region 8      Santa Ana River, Reach 4
LOE ID:	236530
Pollutant:	Naphthalene
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	13
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 13 samples exceeded the water quality threshold for Naphthalene.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA recommended naphthalene criterion for the protection of freshwater aquatic life is 620 ug/l. (EPA 440/5-80-059)
Guideline Reference:	Ambient Water Quality Criteria for Naphthalene
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132874	Region 8
Santa Ana River, Reach 4

Pollutant:	Nickel
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 132874, Nickel Region 8      Santa Ana River, Reach 4
LOE ID:	236466
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Nickel.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved nickel criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 52 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	150916	Region 8
Santa Ana River, Reach 4

Pollutant:	Nitrogen
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 150916, Nitrogen Region 8      Santa Ana River, Reach 4
LOE ID:	303256
Pollutant:	Total Nitrogen as N
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	12
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 1 of 12 samples exceeded the water quality standard for Nitrogen, Inorganic.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 10 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857)
Temporal Representation:	The samples were collected between the dates of 2014-07-23 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 150916, Nitrogen Region 8      Santa Ana River, Reach 4
LOE ID:	303255
Pollutant:	Total Nitrogen as N
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Groundwater Recharge
Number of Samples:	12
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 1 of 12 samples exceeded the water quality standard for Nitrogen, Inorganic.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Site-Specific Objective: The concentration of Total Inorganic Nitrogen shall not exceed 10 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857)
Temporal Representation:	The samples were collected between the dates of 2014-07-23 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132876	Region 8
Santa Ana River, Reach 4

Pollutant:	Oxygen, Dissolved
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 3.2 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 conventional or other pollutants (Table 3.2 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:	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 132876, Oxygen, Dissolved Region 8      Santa Ana River, Reach 4
LOE ID:	236879
Pollutant:	Oxygen, Dissolved
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 Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved oxygen content of surface waters shall not be depressed below 5 mg/L for waters designated WARM as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: SAR-5 (Santa Ana River upstream of Mission Blvd.).
Temporal Representation:	The samples were collected between the dates of 2019-07-30 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
Line of Evidence (LOE) for Decision ID 132876, Oxygen, Dissolved Region 8      Santa Ana River, Reach 4
LOE ID:	236953
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
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 Middle Santa Ana River TMDL Monitoring Project data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved oxygen content of surface waters shall not be depressed below 5 mg/L for waters designated WARM as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the dates of 2019-07-31 and 2019-09-04
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 132876, Oxygen, Dissolved Region 8      Santa Ana River, Reach 4
LOE ID:	236863
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved oxygen content of surface waters shall not be depressed below 5 mg/L for waters designated WARM as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2012-09-13 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132876, Oxygen, Dissolved Region 8      Santa Ana River, Reach 4
LOE ID:	237111
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	35
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Regional Monitoring Program data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 35 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved oxygen content of surface waters shall not be depressed below 5 mg/L for waters designated WARM as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the dates of 2018-06-14 and 2019-11-25
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 132876, Oxygen, Dissolved Region 8      Santa Ana River, Reach 4
LOE ID:	236943
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	10
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Regional Monitoring Program data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved oxygen content of surface waters shall not be depressed below 5 mg/L for waters designated WARM as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the dates of 2016-08-25 and 2017-08-17
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 132876, Oxygen, Dissolved Region 8      Santa Ana River, Reach 4
LOE ID:	236907
Pollutant:	Oxygen, Dissolved
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 Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Oxygen, Dissolved.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved oxygen content of surface waters shall not be depressed below 5 mg/L for waters designated WARM as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: SAR-2a (Santa Ana River upstream of RIX Outfall).
Temporal Representation:	The samples were collected between the dates of 2019-07-30 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

DECISION ID	132881	Region 8
Santa Ana River, Reach 4

Pollutant:	PCBs (Polychlorinated biphenyls)
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132881, PCBs (Polychlorinated biphenyls) Region 8      Santa Ana River, Reach 4
LOE ID:	237245
Pollutant:	PCBs (Polychlorinated biphenyls)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 7 samples exceeded the water quality threshold for PCBs (Polychlorinated biphenyls). Although a total of 13 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The PCB, total aroclors 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:	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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132878	Region 8
Santa Ana River, Reach 4

Pollutant:	Parathion
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 132878, Parathion Region 8      Santa Ana River, Reach 4
LOE ID:	237219
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 Santa Ana Region data for Santa Ana River, Reach 4 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 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA recommended freshwater aquatic life ambient water quality chronic criteria for parathion is 0.013 ug/L.
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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132879	Region 8
Santa Ana River, Reach 4

Pollutant:	Pentachlorophenol (PCP)
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 132879, Pentachlorophenol (PCP) Region 8      Santa Ana River, Reach 4
LOE ID:	237247
Pollutant:	Pentachlorophenol (PCP)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Pentachlorophenol.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The pentachlorophenol criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is pH dependent. The criterion using a default pH value of 7.8 (when pH data is not present) is 15 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2015-06-17
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132899	Region 8
Santa Ana River, Reach 4

Pollutant:	Phorate
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132899, Phorate Region 8      Santa Ana River, Reach 4
LOE ID:	237634
Pollutant:	Phorate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Phorate. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132905	Region 8
Santa Ana River, Reach 4

Pollutant:	Phosmet
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132905, Phosmet Region 8      Santa Ana River, Reach 4
LOE ID:	237636
Pollutant:	Phosmet
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	7
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 7 samples exceeded the water quality threshold for Phosmet. Although a total of 13 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132882	Region 8
Santa Ana River, Reach 4

Pollutant:	Selenium
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 132882, Selenium Region 8      Santa Ana River, Reach 4
LOE ID:	237576
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Selenium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132882, Selenium Region 8      Santa Ana River, Reach 4
LOE ID:	237795
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Selenium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132883	Region 8
Santa Ana River, Reach 4

Pollutant:	Silver
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 132883, Silver Region 8      Santa Ana River, Reach 4
LOE ID:	237557
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Silver.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved silver criterion maximum concentration (CMC) to protect aquatic life in freshwater is hardnesss dependent. The criterion when calculated using a default hardness of 100 mg/L is 3.4 ug/L. This criterion was divided by 2 in order to better represent a CMC value as specified in footnote (g) of Table (b)(1) of the 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	151779	Region 8
Santa Ana River, Reach 4

Pollutant:	Simazine
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 151779, Simazine Region 8      Santa Ana River, Reach 4
LOE ID:	307408
Pollutant:	Simazine
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Simazine.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	USEPA National Recommended Ambient Water Quality Criteria Aquatic Life Protection Instantaneous Max for simazine: 10 ug/L.
Guideline Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2015-06-17
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132885	Region 8
Santa Ana River, Reach 4

Pollutant:	Temperature, water
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 3.2 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 conventional or other pollutants (Table 3.2 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:	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 132885, Temperature, water Region 8      Santa Ana River, Reach 4
LOE ID:	238127
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
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 Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Temperature.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The temperature of waters designated WARM shall not be raised above 90 degrees F June through October or above 78 degrees F during the rest of the year as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: SAR-2a (Santa Ana River upstream of RIX Outfall).
Temporal Representation:	The samples were collected between the dates of 2018-07-31 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
Line of Evidence (LOE) for Decision ID 132885, Temperature, water Region 8      Santa Ana River, Reach 4
LOE ID:	237830
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	26
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Regional Monitoring Program data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 26 samples exceeded the water quality threshold for Temperature.
Data Reference:	Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The temperature of waters designated WARM shall not be raised above 90 degrees F June through October or above 78 degrees F during the rest of the year as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the dates of 2016-09-01 and 2019-11-25
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 132885, Temperature, water Region 8      Santa Ana River, Reach 4
LOE ID:	238039
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
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 Middle Santa Ana River TMDL Monitoring Project data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Temperature.
Data Reference:	Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The temperature of waters designated WARM shall not be raised above 90 degrees F June through October or above 78 degrees F during the rest of the year as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the dates of 2019-08-07 and 2019-09-04
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 132885, Temperature, water Region 8      Santa Ana River, Reach 4
LOE ID:	238126
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
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 Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Temperature.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The temperature of waters designated WARM shall not be raised above 90 degrees F June through October or above 78 degrees F during the rest of the year as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: SAR-5 (Santa Ana River upstream of Mission Blvd.).
Temporal Representation:	The samples were collected between the dates of 2018-07-31 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
Line of Evidence (LOE) for Decision ID 132885, Temperature, water Region 8      Santa Ana River, Reach 4
LOE ID:	237966
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Temperature.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The temperature of waters designated WARM shall not be raised above 90 degrees F June through October or above 78 degrees F during the rest of the year as a result of controllable water quality factors (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2012-09-13 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132886	Region 8
Santa Ana River, Reach 4

Pollutant:	Terbufos
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 132886, Terbufos Region 8      Santa Ana River, Reach 4
LOE ID:	238075
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 Santa Ana Region data for Santa Ana River, Reach 4 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 13 samples were collected, 13 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
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:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132887	Region 8
Santa Ana River, Reach 4

Pollutant:	Tetrachlorvinphos
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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132887, Tetrachlorvinphos Region 8      Santa Ana River, Reach 4
LOE ID:	238095
Pollutant:	Tetrachlorvinphos
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 0 of the 8 samples exceeded the water quality threshold for Tetrachlorvinphos. Although a total of 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The evaluation guideline for stirophos (tetrachlorvinphos) is the USEPA Aquatic Life Benchmark of 0.125 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132888	Region 8
Santa Ana River, Reach 4

Pollutant:	Thallium
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 132888, Thallium Region 8      Santa Ana River, Reach 4
LOE ID:	237869
Pollutant:	Thallium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Thallium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA Quality Criteria for Water (Gold Book) states that thallium chronic toxicity to one species of fish occurs at concentrations as low as 20 ug/L after 2,600 hours of exposure. (USEPA, 1986)
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132888, Thallium Region 8      Santa Ana River, Reach 4
LOE ID:	237868
Pollutant:	Thallium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Thallium.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The USEPA Quality Criteria for Water (Gold Book) states that thallium chronic toxicity to one species of fish occurs at concentrations as low as 20 ug/L after 2,600 hours of exposure. (USEPA, 1986)
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132889	Region 8
Santa Ana River, Reach 4

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 pollutant is being considered for placement on the CWA 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. Three lines of evidence are available in the administrative record to assess this pollutant. Zero of the 42 samples exceed the WARM Total Dissolved Solids 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 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 42 samples exceed the WARM Total Dissolved Solids objective and this does 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:	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:	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 132889, Total Dissolved Solids Region 8      Santa Ana River, Reach 4
LOE ID:	240065
Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality standard for Total Dissolved Solids.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 550 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857)
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	RC NPDES MS4 MP
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132889, Total Dissolved Solids Region 8      Santa Ana River, Reach 4
LOE ID:	82358
Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	28
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Numeric data generated from 28 samples collected had no exceedences of the site-specific objective.
Data Reference:	Data for Metals and Other Inorganic Pollutants in Orange County Water District, 1994-2010.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The site-pecific objective for Total Dissolved Solids at Santa Ana River, Reach 4 according to table 4-1 of the Santa Ana Basin plan is 550 mg/L.
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Data was collected from the SAR-LACADENA-01 SAR and RIVERSIDEAVE-01 stations.
Temporal Representation:	Data was collected approximately twice per quarter from February 1994 to August 2009.
Environmental Conditions:
QAPP Information:	The samples were collected under the Orange County Water District Main Laboratory Quality Assurance Manual. November 2009.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 132889, Total Dissolved Solids Region 8      Santa Ana River, Reach 4
LOE ID:	240066
Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Groundwater Recharge
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality standard for Total Dissolved Solids.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	Site-Specific Objective: The concentration of Total Dissolved Solids shall not exceed 550 mg/L in this waterbody (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857)
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	RC NPDES MS4 MP
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132890	Region 8
Santa Ana River, Reach 4

Pollutant:	Toxaphene
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 132890, Toxaphene Region 8      Santa Ana River, Reach 4
LOE ID:	238041
Pollutant:	Toxaphene
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Toxaphene. Although a total of 13 samples were collected, 13 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The toxaphene criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0002 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132891	Region 8
Santa Ana River, Reach 4

Pollutant:	Toxicity
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 132891, Toxicity Region 8      Santa Ana River, Reach 4
LOE ID:	238144
Pollutant:	Toxicity
LOE Subgroup:	Toxicity
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	6
Number of Exceedances:	1
Data and Information Type:	TOXICITY TESTING
Data Used to Assess Water Quality:	1 of the 6 samples collected by Santa Ana Region for Santa Ana River, Reach 4 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 and the same location. The following organisms and parameters were utilized for the toxicity tests: Selenastrum capricornutum for Total Cell Count, Ceriodaphnia dubia for Survival, Pimephales promelas for Survival. The following tests exhibited toxicity: Selenastrum capricornutum for Total Cell Count on 2016-08-17.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The sample is toxic when the response of the organisms exposed to the sample is significantly different (worse) than the response of the organisms exposed to the laboratory control based on statistical hypothesis testing.  An exceedance is counted when the significant effect code is “Significant; Less Similarity,” which means that the sample result is significantly different than the control result, and the percent effect is greater than the evaluation threshold.  The default evaluation threshold is 20% unless otherwise stated.
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 monitoring site: 801AHG857 ( Santa Ana River at Highgrove ).
Temporal Representation:	The samples were collected between the dates of 2016-08-17 and 2019-06-10.
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132892	Region 8
Santa Ana River, Reach 4

Pollutant:	Trichlorfon
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 132892, Trichlorfon Region 8      Santa Ana River, Reach 4
LOE ID:	238057
Pollutant:	Trichlorfon
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Trichlorfon. Although a total of 14 samples were collected, 14 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	The evaluation guideline for trichlorfon is the USEPA Aquatic Life Benchmark of 0.0057 ug/L for an invertebrate (chronic).
Guideline Reference:	OPP Aquatic Life Benchmarks
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	Data for this waterbody were collected over the date range 2013-07-10 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132893	Region 8
Santa Ana River, Reach 4

Pollutant:	Zinc
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 132893, Zinc Region 8      Santa Ana River, Reach 4
LOE ID:	237909
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Zinc.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The dissolved zinc criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 120 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132858	Region 8
Santa Ana River, Reach 4

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:	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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132858, alpha-Endosulfan (Endosulfan 1) Region 8      Santa Ana River, Reach 4
LOE ID:	236280
Pollutant:	alpha-Endosulfan (Endosulfan 1)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	10
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality threshold for Endosulfan I.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The endosulfan I (alpha-endosulfan) 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132877	Region 8
Santa Ana River, Reach 4

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:	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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 132877, beta-Endosulfan (Endosulfan 2) Region 8      Santa Ana River, Reach 4
LOE ID:	236282
Pollutant:	beta-Endosulfan (Endosulfan 2)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	10
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality threshold for Endosulfan II.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The endosulfan II (beta-endosulfan) 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: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2013-07-10 and 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132880	Region 8
Santa Ana River, Reach 4

Pollutant:	pH
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 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Five lines of evidence are available in the administrative record to assess this pollutant. Three of the 47 samples exceed the WARM pH 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 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. Three of the 47 samples exceed the WARM pH objective and this does 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:	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:	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 132880, pH Region 8      Santa Ana River, Reach 4
LOE ID:	237241
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	14
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 1 of 14 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The pH of inland surface waters shall not be raised above 8.5 or depressed below 6.5 as a result of controllable water quality factors (The Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: 801AHG857 (Santa Ana River at Highgrove).
Temporal Representation:	The samples were collected between the dates of 2012-09-13 and 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN
Line of Evidence (LOE) for Decision ID 132880, pH Region 8      Santa Ana River, Reach 4
LOE ID:	237427
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 Middle Santa Ana River TMDL Monitoring Project data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The pH of inland surface waters shall not be raised above 8.5 or depressed below 6.5 as a result of controllable water quality factors (The Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the dates of 2019-08-07 and 2019-09-04
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 132880, pH Region 8      Santa Ana River, Reach 4
LOE ID:	237512
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	26
Number of Exceedances:	0
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Regional Monitoring Program data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 0 of 26 samples exceeded the water quality threshold for pH.
Data Reference:	Field, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The pH of inland surface waters shall not be raised above 8.5 or depressed below 6.5 as a result of controllable water quality factors (The Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: P3-SBC1 (Santa Ana River Reach 4 above S. Riverside Avenue Bridge).
Temporal Representation:	The samples were collected between the dates of 2016-09-01 and 2019-11-25
Environmental Conditions:
QAPP Information:	CDM Smith. 2019. Santa Ana River Watershed Bacteria Monitoring Program.
QAPP Information Reference(s):	Santa Ana River Watershed Bacteria Monitoring Program
Line of Evidence (LOE) for Decision ID 132880, pH Region 8      Santa Ana River, Reach 4
LOE ID:	237233
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 1 of 2 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The pH of inland surface waters shall not be raised above 8.5 or depressed below 6.5 as a result of controllable water quality factors (The Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: SAR-5 (Santa Ana River upstream of Mission Blvd.).
Temporal Representation:	The samples were collected between the dates of 2018-07-31 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.
Line of Evidence (LOE) for Decision ID 132880, pH Region 8      Santa Ana River, Reach 4
LOE ID:	237511
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Warm Freshwater Habitat
Number of Samples:	2
Number of Exceedances:	1
Data and Information Type:	PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality:	Water Board staff assessed Santa Ana River Dischargers Association data for Santa Ana River, Reach 4 to determine beneficial use support and results are as follows: 1 of 2 samples exceeded the water quality threshold for pH.
Data Reference:	Field, Habitat, Tissue data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The pH of inland surface waters shall not be raised above 8.5 or depressed below 6.5 as a result of controllable water quality factors (The Water Quality Control Plan, Santa Ana Basin, Chapter 4 Water Quality Objectives, Inland Surface Waters).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	The samples were collected at 1 monitoring site: SAR-2a (Santa Ana River upstream of RIX Outfall).
Temporal Representation:	The samples were collected between the dates of 2018-07-31 and 2019-07-30
Environmental Conditions:
QAPP Information:	SWRCB. 2018. This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements..
QAPP Information Reference(s):	This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

DECISION ID	149276	Region 8
Santa Ana River, Reach 4

Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
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 are available in the administrative record to assess this pollutant. Two of the four water samples exceed the WARM DDT criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Two of the four water samples exceed the WARM DDT criterion and this exceeds the allowable frequency listed in Table 3.1 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
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 149276, DDT (Dichlorodiphenyltrichloroethane) Region 8      Santa Ana River, Reach 4
LOE ID:	236350
Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 2 of the 4 samples exceeded the water quality threshold for DDT(p,p'). Although a total of 10 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-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 (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2013-07-10 to 2019-09-16
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN

DECISION ID	132875	Region 8
Santa Ana River, Reach 4

Pollutant:	Oil and Grease
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
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 are available in the administrative record to assess this pollutant. Three of the three samples exceed the WARM Oil guideline. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Three of the three samples exceed the WARM Oil guideline, and this exceeds the allowable frequency listed in Table 3.1 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
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 132875, Oil and Grease Region 8      Santa Ana River, Reach 4
LOE ID:	236828
Pollutant:	Oil and Grease
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Warm Freshwater Habitat
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 Santa Ana Region data for Santa Ana River, Reach 4 to determine beneficial use support and the results are as follows: 3 of the 3 samples exceeded the water quality threshold for OilandGrease; HEM. Although a total of 7 samples were collected, 4 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:	Field, Habitat, Toxicity, WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 8.
SWAMP Data:	Non-SWAMP
Water Quality Objective/Criterion:	The concentrations of toxic pollutants in the water column, sediments or biota shall not adversely affect beneficial uses (Water Quality Control Plan for the Santa Ana River Basin).
Objective/Criterion Reference:	Water Quality Control Plan, Santa Ana River Basin
Evaluation Guideline:	According to the USEPA Quality Criteria for Water (Gold Book), concentrations of oil at 0.001 mg/L can harm aquatic life. (USEPA, 1986)
Guideline Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Spatial Representation:	The samples were collected at 1 monitoring site (801AHG857).
Temporal Representation:	Data for this waterbody was collected over the date range 2015-06-17 to 2020-06-03
Environmental Conditions:
QAPP Information:	Riverside County Watershed Protection. 2021. VOLUME II: QUALITY ASSURANCE PROJECT PLAN.
QAPP Information Reference(s):	VOLUME II: QUALITY ASSURANCE PROJECT PLAN