Draft California 2018 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Carson River, West Fork (Hope Valley to Woodfords)
Water Body ID: CAR6331001320011213134239
Water Body Type: River & Stream
 
DECISION ID
79455
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Indicator Bacteria
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)(2016)
Revision Status Revised
Reason for Delisting: Applicable WQS attained; reason for recovery unspecified
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

The listing was previously for "Pathogens" and was changed to "Fecal Coliform" during the 2012 Listing Cycle. For the 2018 cycle the pollutant name has been changed to "Indicator Bacteria" for clarity and consistency.

Ten lines of evidence are available in the administrative record to assess this pollutant. E. coli data assessed for the REC-1 beneficial use based on the 2018 water quality objective for indicator for bacteria: 0 of 74 samples exceed the water quality objective for E. coli assessed as a geometric mean; 0 of 46 sample exceed the water quality objective for E. coli assessed as a Statistical Threshold Value (STV). Fecal coliform data collected during this assessment cycle has also been assessed: 0 of 130 samples exceed the objective for fecal coliform geometric mean assessed against the MUN beneficial use; 2 of 44 samples exceed the objective for fecal coliform as a threshold value assessed against the MUN beneficial use. Two LOEs from a previous cycle have been relocated as the water body was remapped for the 2018 cycle. These LOE's also support the removal of the waterbody segment from the 303(d) list: 7 of 78 samples exceed the objective for fecal coliform geometric mean, and 5 of 78 samples exceed the objective for fecal coliform threshold value, both for the REC-1 beneficial use. These data support the removal of this waterbody segment/pollutant combination from the 303(d) list.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for 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. 0 of 74 E. coli geometric mean samples and 0 of 130 fecal coliform log-mean samples exceeded the applicable water quality objectives for the REC-1 and MUN beneficial uses and this does not exceed the allowable frequency listed 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.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100528
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 78
Number of Exceedances: 5
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Five of the 78 samples exceeded the Fecal Coliform objective.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The fecal coliform concentration shall not exceed more than 40/100 ml.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at Carson River, W Fork, Crystal Springs Rd.
Temporal Representation: The samples were collected between January 2004 to June 2010.
Environmental Conditions:
QAPP Information: The samples were collected under the South Tahoe Public Utility District Laboratory Quality Assurance Program. Monitoring and Reporting Program NO. R6T-2004-0010.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100051
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 7
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and the results are as follows: 0 of the 7 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 633WFCB03
Temporal Representation: The samples were collected between the days of 2014-12-08 and 2015-11-19 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100151
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 74
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed RWB6_BACT_Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and the results are as follows: 0 of the 74 samples exceeded the geomean water quality standard for E. coli. This is a six week rolling geomean that is calculated weekly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a six-week rolling GEOMETRIC MEAN (GM) of Escherichia coli (E. coli) not to exceed 100 colony forming units per 100 milliliters (cfu/100 mL) (calculated weekly).
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): 633WFCB03
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2015-08-18 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 99980
 
Pollutant: Escherichia coli (E. coli)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 39
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed RWB6_BACT_Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and the results are as follows: 0 of the 39 samples exceeded the Statistical Threshold Value (STV) water quality standard for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).
Objective/Criterion Reference: Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 633WFCB03
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2015-08-18 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 129120
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 38
Number of Exceedances: 2
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed RWB6_BACT_Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and the results are as follows: 2 of the 38 samples exceeded the water quality standard for Coliform, Fecal. The water quality standard is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. (Lahontan Region Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 633WFCB03
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2015-08-18 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 129450
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and the results are as follows: 0 of the 6 samples exceeded the water quality standard for Coliform, Fecal. The water quality standard is based on a 10% exceedance rate that is calculated monthly.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. (Lahontan Region Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 633WFCB03
Temporal Representation: The samples were collected between the days of 2014-12-08 and 2015-11-19 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 129164
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and the results are as follows: 0 of the 6 samples exceeded the logmean water quality standard for Coliform, Fecal. This is a 30-day rolling logmean that is calculated daily.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml. (Lahontan Region Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 633WFCB03
Temporal Representation: The samples were collected between the days of 2014-12-08 and 2015-11-19 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 129259
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 124
Number of Exceedances: 0
 
Data and Information Type: PATHOGEN MONITORING
Data Used to Assess Water Quality: Water Board staff assessed RWB6_BACT_Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and the results are as follows: 0 of the 124 samples exceeded the logmean water quality standard for Coliform, Fecal. This is a 30-day rolling logmean that is calculated daily.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Regional Water Board 6 Bacteria Monitoring.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml. (Lahontan Region Basin Plan)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s), station(s): 633WFCB03
Temporal Representation: The samples were collected between the days of 2010-08-31 and 2015-08-18 .
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100482
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 78
Number of Exceedances: 7
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Seven of the 78 samples exceeded the Fecal Coliform objective.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml. Water Quality Control Plan for the Lahontan Region.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at Carson River, W Fork, Crystal Springs Rd.
Temporal Representation: The samples were collected between January 2004 to June 2010.
Environmental Conditions:
QAPP Information: The samples were collected under the South Tahoe Public Utility District Laboratory Quality Assurance Program. Monitoring and Reporting Program NO. R6T-2004-0010.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79455, Indicator Bacteria
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 4600
 
Pollutant: Pathogens
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
 
DECISION ID
76498
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Sodium
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Delist from 303(d) list (TMDL required list)(2016)
Revision Status Revised
Reason for Delisting: Other
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Five lines of evidence, three which evaluate data for the AG beneficial use, and one each which evaluate data for the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 43 samples exceeded the water quality objective for the AG beneficial use assessment; 0 of 5 samples evaluated for the MUN beneficial use exceed the water quality objective; Data evaluated for the COLD beneficial use did not pass the quantitation checks required by the 2018 Integrated Report and the computed sample size for this assessment is zero: 0 of 0 samples exceed the objective for the COLD beneficial use.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for 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. 0 of 43 samples exceeded the objective and this does not exceed the allowable frequency listed 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.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded.
 
 
Line of Evidence (LOE) for Decision ID 76498, Sodium
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 97150
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
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 SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality standard for Sodium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: Per the Drinking Water Standards and Health Advisories (USEPA 2012), the health advisory for sodium for individuals on a sodium-restricted diet is 20 mg/l.
Guideline Reference: 2012 Edition of the Drinking Water Standards and Health Advisories
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (633WFCB03)
Temporal Representation: The samples were collected between the dates of 2014-12-08 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 76498, Sodium
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 98539
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Agricultural Supply
 
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 SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality standard for Sodium.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. At or below the sodium threshold of 69 mg/L, agricultural uses of water should not be limited.
Guideline Reference: Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (633WFCB03)
Temporal Representation: The samples were collected between the dates of 2014-12-08 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 76498, Sodium
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 5688
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 19
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Table 3 of the Region 6 staff report for the Basin Plan amendments summarizes annual average SAR values for the West Fork Carson River. Lahontan RWQCB staff calculated these averages using historical data on SAR or the component ions. For data collected by the South Tahoe Public Utility District between 1984 and 2002, annual average SAR values ranged from 0.3 to 0.4. The mean annual average value was 0.3. The water quality objective (SAR =1) was attained.
Data Reference: Self-monitoring monthly reports from 2000 to 2003. Including Carson River and Indian Creek
  Self-monitoring monthly reports from 1997 to 2000. Including Carson River and Indian Creek
  Memorandum: Summary of water quality analysis for potential CWA 303(d) listing of the lower West Fork of the Carson River. South Lake Tahoe, CA: Lahontan RWQCB
  2006. Technical Staff Report for Revised Sodium-Related Standards for the Carson and Walker River Watersheds
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The water quality objective for Sodium Adsorption Ratio (SAR) in the West Fork Carson River is a limit of 1, as an annual average. (As a ratio, SAR has no units.) The objective includes the formula for calculating SAR and natural sources exclusion language.

The approved plan amendments have not yet been physically incorporated into the text of the Basin Plan. A copy of the amendments is included in the administrative record of the 2008 Integrated Report and is used as a reference in this LOE.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station in this segment was sampled.
Temporal Representation: The data cited above were collected at approximately monthly intervals between 1984 and 2002, for 211 samples in all. Nineteen annual average calculations were done.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley. It joins the East Fork to form the Carson River in Nevada. Water from the West Fork is used for irrigation of pasture and some field crops in the Carson Valley in California, and it contributes to the irrigation supply in Nevada.
QAPP Information: The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 76498, Sodium
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 4601
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 76498, Sodium
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100477
 
Pollutant: Sodium
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Agricultural Supply
 
Number of Samples: 19
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Table 3 of the Region 6 staff report for the Basin Plan amendments summarizes annual average SAR values for the West Fork Carson River. Lahontan RWQCB staff calculated these averages using historical data on SAR or the component ions. For data collected by the South Tahoe Public Utility District between 1984 and 2002, annual average SAR values ranged from 0.2 to 0.3. The mean annual average value was 0.3. The water quality objective (SAR =1) was attained.
Data Reference: Self-monitoring monthly reports from 2000 to 2003. Including Carson River and Indian Creek
  Self-monitoring monthly reports from 1997 to 2000. Including Carson River and Indian Creek
  Memorandum: Summary of water quality analysis for potential CWA 303(d) listing of the lower West Fork of the Carson River. South Lake Tahoe, CA: Lahontan RWQCB
  2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units
  2006. Technical Staff Report for Revised Sodium-Related Standards for the Carson and Walker River Watersheds
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The water quality objective for Sodium Adsorption Ratio (SAR) in the West Fork Carson River is a limit of 1, as an annual average. (As a ratio, SAR has no units.) The objective includes the formula for calculating SAR and natural sources exclusion language.

The approved plan amendments have not yet been physically incorporated into the text of the Basin Plan. A copy of the amendments is included in the administrative record of the 2008 Integrated Report and is used as a reference in this LOE.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
  2006. Amendments to the Water Quality Control Plan for the Lahontan Region: Revised Sodium-Related Standards for the Carson and Walker River Watersheds. Adopted October 12, 2006 under Resolution R6T-2006-0047
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The data were collected in a canal diverting water from the West Fork Carson River upstream of the USGS gage at Woodfords.
Temporal Representation: The data cited above were collected at approximately monthly intervals between 1984 and 2002, for 224 samples in all. Nineteen annual average calculations were done.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley. It joins the East Fork to form the Carson River in Nevada. Water from the West Fork is used for irrigation of pasture and some field crops in the Carson Valley in California, and it contributes to the irrigation supply in Nevada.
QAPP Information: The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
78956
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Chloride
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2022
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. 24 of the 36 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. 24 of 36 samples exceeded the objective and this exceeds the allowable frequency listed 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 met.
 
Regional Board Staff 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.
 
 
Line of Evidence (LOE) for Decision ID 78956, Chloride
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100448
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 30
Number of Exceedances: 22
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected for 30 years between 1980 and 2010 (no data were collected in 1982). For those 30 years, the annual average exceeded 1.0 mg/L on 22 of the years.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The site-specific objective in Lahontan Basin Plan Table 3-14 is 1.0 mg/L as a mean of monthly means. The objective applies upstream from Woodfords under the Tributary Rule.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample collected at the following locations: SW-01-Carson River, W Fork, Crystal Springs Rd D-1-Carson River, West Fork @ Diversion
Temporal Representation: Samples collected between 1980 and 2010.
Environmental Conditions:
QAPP Information: South Tahoe Public Utility District Laboratory Quality Assurance Program (by Terry Powers, Laboratory Director). March 30, 2009.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 78956, Chloride
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 96860
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Not Specified
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Headwaters to Woodfords) to determine beneficial use support and results are as follows: 2 of 6 samples exceeded the water quality standard for Chloride. The two that exceeded were in 2014 and 2015.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The site specific objective in the Lahontan Basin Plan for chloride for the West Form Carson River at Woodfords (table 3-14) is 1.0 mg/L mean of monthly mean. This objective is applied as per the tributary rule as stated in Chapter 2 of the Basin Plan: "additional beneficial uses may apply to waters with in these categories under the tributary rule, which provides that water quality standards for specific waterbodies apply upstream to tributaries for which no site-specific standards have been adopted."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (633WCR002, 633WFCB03)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
70168
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Nitrogen
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2022
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: The WF Carson River was re-segmented during the 2018 cycle, so some lines of evidence have been moved to an adjacent segment depending on where the data was collected. LOE 100486 duplicates the data from LOE 27599 that was originally located in the headwaters segment but that now corresponds to this segment.

For the 2018 Listing Cycle this pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under section 4.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence, one which assesses Total Nitrogen data for the COLD beneficial use and a placeholder LOE for Nitrogen data assessed prior to 2006, are available in the administrative record to assess this pollutant. 1 of 1 available samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination 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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 1 of 1 samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 28 samples are needed to determine if a beneficial use is fully supported using table 4.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff 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.
 
 
Line of Evidence (LOE) for Decision ID 70168, Nitrogen
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 4599
 
Pollutant: Nitrogen
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 0
Number of Exceedances: 0
 
Data and Information Type: Not Specified
Data Used to Assess Water Quality: Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: Placeholder reference pre-2006 303(d)
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Unspecified
Objective/Criterion Reference: Placeholder reference pre-2006 303(d)
 
Evaluation Guideline: Unspecified
Guideline Reference: Placeholder reference pre-2006 303(d)
 
Spatial Representation: Unspecified
Temporal Representation: Unspecified
Environmental Conditions: Unspecified
QAPP Information: Unspecified
QAPP Information Reference(s):
 
Line of Evidence (LOE) for Decision ID 70168, Nitrogen
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100486
 
Pollutant: Total Nitrogen as N
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: This segment was placed on the Section 303(d) list in 2002 on the basis of calculations by RWQCB staff using data collected by the South Tahoe Public Utility District between 1981 and 2000. The mean of monthly means for total nitrogen in 2000 was 0.20 mg/L, exceeding the objective.
Data Reference: Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The water quality objective for total nitrogen in this segment is 0.15 mg/L, expressed as an annual mean of monthly means. This is a running average incorporating historical data.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The South Tahoe PUD data were collected in a diversion ditch upstream of the USGS gage at Woodfords.
Temporal Representation: The South Tahoe PUD samples were collected approximately monthly between 1981 and 2000.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use.
QAPP Information: The South Tahoe Public Utility District maintains its own laboratory and has a quality assurance program acceptable to the RWQCB.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
78852
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Nitrogen, Nitrate
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2022
Impairment from Pollutant or Pollution: Pollution
 
Regional Board Staff Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess pollutant. 3 of 10 samples exceed the water quality objective for the COLD beneficial use.

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. 3 of 10 samples exceeded the objective and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Staff 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.
 
 
Line of Evidence (LOE) for Decision ID 78852, Nitrogen, Nitrate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100516
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 9
Number of Exceedances: 2
 
Data and Information Type: Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: Two out of 9 annual means of monthly means exceeded the water quality objective for nitrate as nitrogen expressed as an annual mean of monthly means. A total of 102 samples were collected from the two sites.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The site specific objective for West Fork Carson River at Woodfords for nitrate as nitrogen is is 0.02 mg/L as means of monthly means.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at SW-01 Carson River, W Fork, Crystal Springs Rd
Temporal Representation: Samples were collected monthly from January 2002 to June 2010.
Environmental Conditions:
QAPP Information: Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 78852, Nitrogen, Nitrate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100487
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: This segment was placed on the Section 303(d) list in 2002 on the basis of calculations by RWQCB staff using data collected by the South Tahoe Public Utility District between 1981 and 2000. The mean of monthly means for nitrate in 2000 was 0.04 mg/L, exceeding the objective.
Data Reference: Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The water quality objective for nitrate (as N) in this segment is 0.02 mg/L, expressed as an annual mean of monthly means. This is a running average incorporating historical data.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The South Tahoe PUD data were collected in a diversion ditch upstream of the USGS gage at Woodfords.
Temporal Representation: The South Tahoe PUD samples were collected approximately monthly between 1981 and 2000.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use.
QAPP Information: The South Tahoe Public Utility District maintains its own laboratory and has a quality assurance program acceptable to the RWQCB.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
78769
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Sulfates
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2025
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess pollutant. 26 of the 34 samples exceed the water quality objective for the cold beneficial use.

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. 26 of 34 samples exceeded the objective and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
 
Regional Board Staff 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.
 
 
Line of Evidence (LOE) for Decision ID 78769, Sulfates
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100450
 
Pollutant: Sulfates
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 28
Number of Exceedances: 22
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected over a 28 year period. On 22 of those years, the annual average exceeded 2.0 mg/L. Exceedances for years 1983-1986 were not considered since the detection limit was above the site-specific objective.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The site-specific objective for sulfate is 2.0 mg/L as a mean of monthly means (applied upstream through the Tributary Rule from the West Fork Carson River at Woodfords station). See Basin Plan Table 3-14.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample collected at the following locations: SW-01-Carson River, W Fork, Crystal Springs Rd D-1-Carson River, West Fork @ Diversion
Temporal Representation: Samples collected between 9/12/1983 and 6/2/2010.
Environmental Conditions:
QAPP Information: South Tahoe Public Utility District Laboratory Quality Assurance Program (by Terry Powers, Laboratory Director). March 30, 2009.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 78769, Sulfates
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 96862
 
Pollutant: Sulfates
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 4
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Headwaters to Woodfords) to determine beneficial use support and results are as follows: 4 of 6 samples exceeded the water quality standard for Sulfate. Exceedances were in 2010, 2013 , 2014, and 2015.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data:
 
Water Quality Objective/Criterion: The site specific objective in the Lahontan Basin Plan for sulfate for the West Form Carson River at Woodfords (table 3-14) is 2.0 mg/L mean of monthly mean. This objective is applied as per the tributary rule as stated in Chapter 2 of the Basin Plan: "additional beneficial uses may apply to waters with in these categories under the tributary rule, which provides that water quality standards for specific waterbodies apply upstream to tributaries for which no site-specific standards have been adopted."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (633WCR002, 633WFCB03)
Temporal Representation: The samples were collected between the dates of 2010-08-31 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
73028
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Total Dissolved Solids
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2025
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. Ten of the 37 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. Ten of 37 samples exceeded the objective and this exceeds the allowable frequency listed 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 met.
 
Regional Board Staff 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.
 
 
Line of Evidence (LOE) for Decision ID 73028, Total Dissolved Solids
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 96864
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Headwaters to Woodfords) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality standard for Total Dissolved Solids.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The site specific objective in the Lahontan Basin Plan for TDS for the West Form Carson River at Woodfords (table 3-14) is 55 mg/L mean of monthly means. This objective is applied as per the tributary rule as stated in Chapter 2 of the Basin Plan: "additional beneficial uses may apply to waters with in these categories under the tributary rule, which provides that water quality standards for specific waterbodies apply upstream to tributaries for which no site-specific standards have been adopted."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (633WCR002, 633WFCB03)
Temporal Representation: The samples were collected between the dates of 2010-10-20 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 73028, Total Dissolved Solids
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100452
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 31
Number of Exceedances: 8
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected over 31 years. For eight of those years, the annual average exceeded 55 mg/L.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The site-specific objective for total dissolved solids (TDS) is 55 mg/L as a mean of monthly means (applied upstream through the Tributary Rule from the West Fork Carson River at Woodfords station). See Lahontan Basin Plan Table 3-14.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample collected at the following locations: SW-01-Carson River, W Fork, Crystal Springs Rd D-1-Carson River, West Fork @ Diversion
Temporal Representation: Samples collected between 7/8/1980 and 6/2/2010.
Environmental Conditions:
QAPP Information: South Tahoe Public Utility District Laboratory Quality Assurance Program (by Terry Powers, Laboratory Director). March 30, 2009.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
78767
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Turbidity
Final Listing Decision: Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Sources: Source Unknown
Expected TMDL Completion Date: 2025
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for removal from the CWA section 303(d) List under section 4.2 of the Listing Policy. Under this section 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. Seven of the 41 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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 of 41 samples exceeded the objective and this exceeds the allowable frequency listed 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 met.
 
Regional Board Staff 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.
 
 
Line of Evidence (LOE) for Decision ID 78767, Turbidity
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 98228
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Turbidity. For purposes of this assessment the mean of monthly means is calculated on an annual basis, giving two years possible for assessment using this data.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The watershed-wide objective for turbidity in the West Fork Carson River hydrologic unit, as stipulated in the Lahontan Basin Plan page 3-9, is a mean-of-monthly means not to exceed 2 NTU.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (633WFCB03)
Temporal Representation: The samples were collected between the dates of 2014-12-08 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 78767, Turbidity
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100451
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 31
Number of Exceedances: 7
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected over 31 years. For seven of those years, the annual average exceeded 2 NTU.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's objective for turbidity states: "The turbidity shall not be raised above a mean of monthly means value of 2 NTU. (This objective is approximately equal to the State of Nevada standard of 2 NTU annual mean)." This is a watershed-specific objective that differs from the regionwide narrative objective.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample collected at the following locations: SW-01-Carson River, W Fork, Crystal Springs Rd D-1-Carson River, West Fork @ Diversion
Temporal Representation: Samples collected between 7/8/1980 and 6/2/2010.
Environmental Conditions:
QAPP Information: South Tahoe Public Utility District Laboratory Quality Assurance Program (by Terry Powers, Laboratory Director). March 30, 2009.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 78767, Turbidity
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 98198
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold 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 Alpine Watershed Group Monitoring Program data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality standard for Turbidity. For purposes of this assessment the mean of monthly means is calculated on an annual basis, giving eight years possible for assessment using this data.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Alpine Watershed Group Monitoring Program.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The watershed-wide objective for turbidity in the West Fork Carson River hydrologic unit, as stipulated in the Lahontan Basin Plan page 3-9, is a mean-of-monthly means not to exceed 2 NTU.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference: California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (WF-WDFD)
Temporal Representation: The samples were collected between the dates of 2010-09-11 and 2017-03-11
Environmental Conditions:
QAPP Information: Quality Assurance Project Plan for Alpine Watershed Group Volunteer Citizen Water Quality Monitoring Program
QAPP Information Reference(s): Quality Assurance Project Plan for Alpine Watershed Group Volunteer Citizen Water Quality Monitoring Program
 
 
DECISION ID
100963
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: 2, 6- diethylaniline
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of the 4 samples exceed the water quality guideline for either the COLD beneficial use and 0 of 4 samples exceed the guideline for the MUN beneficial use.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples exceeded the guideline in each assessment and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 100963, 2, 6- diethylaniline
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100589
 
Pollutant: 2, 6- diethylaniline
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 100963, 2, 6- diethylaniline
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100494
 
Pollutant: 2, 6- diethylaniline
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
100964
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: 2-chloro-4-isopropylamino-6-amino-s-triazine
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of the 4 samples exceed the water quality guideline for either the COLD beneficial use and 0 of 4 samples exceed the guideline for the MUN beneficial use.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 100964, 2-chloro-4-isopropylamino-6-amino-s-triazine
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100590
 
Pollutant: 2-chloro-4-isopropylamino-6-amino-s-triazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 100964, 2-chloro-4-isopropylamino-6-amino-s-triazine
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100495
 
Pollutant: 2-chloro-4-isopropylamino-6-amino-s-triazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
100965
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Alachlor
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of the 4 samples exceed the water quality guideline for the COLD beneficial use, and 0 of 4 samples exceed the guideline for the MUN beneficial use.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either assessment exceeded the objectives and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 100965, Alachlor
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100496
 
Pollutant: Alachlor
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 100965, Alachlor
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100593
 
Pollutant: Alachlor
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
100966
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

One line of evidence is available in the administrative record to assess this pollutant. 0 of the 5 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 5 samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using table 3.2.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 100966, Alkalinity as CaCO3
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 97057
 
Pollutant: Alkalinity as CaCO3
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold 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 SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality standard for Alkalinity as CaCO3.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The National Recommended Water Quality Criteria for Alkalinity as CaCO3 for the protection of freshwater aquatic life is not less than 20000 ug/L. (National Recommended Water Quality Criteria 2016)
Objective/Criterion Reference: National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Current as of 08/03/2016.
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (633WFCB03)
Temporal Representation: The samples were collected between the dates of 2014-12-08 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
78810
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Ammonia
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Zero of 97 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Zero of 97 samples exceeded the objective and this does not exceed 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 Staff Decision Recommendation: After review of 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.
 
 
Line of Evidence (LOE) for Decision ID 78810, Ammonia
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100518
 
Pollutant: Nitrogen, ammonia (Total Ammonia)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Fish Spawning
 
Number of Samples: 97
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: None of 97 samples exceeded the water quality objective for unionized ammonia. Data were reported as as total ammonia as nitrogen and were converted to unionized ammonia before being compared with the objective. Some samples had temperature or pH values outside the range of the criteria and were not counted.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan objective for unionized ammonia is a function of pH, temperature, and the presence of salmonids. The 4-day chronic criteria for unionized ammonia with salmonids present ranged from 0.0011 mg/L to 0.033 mg/L.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at SW-01 Carson River, W Fork, Crystal Springs Rd.
Temporal Representation: Samples were collected from January 2002 to June 2010.
Environmental Conditions:
QAPP Information: Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79963
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Arsenic
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision no longer applies to this segment of the river due to re-segmentation of WF Carson and it and the attached LOE should be retired.

Text from past cycle
This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79963, Arsenic
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 44013
 
Pollutant: Arsenic
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Arsenic.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for arsenic is 33 mg/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
100967
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of the 4 samples exceed the water quality guideline for the COLD beneficial use assessment, and 0 of 4 samples exceed the guideline for the MUN beneficial use assessment.

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 does not satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 100967, Atrazine
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100594
 
Pollutant: Atrazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 100967, Atrazine
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100497
 
Pollutant: Atrazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
100968
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of the 4 samples exceed the water quality guideline for the COLD beneficial use assessment, and 0 of 4 sample exceed the guideline for the MUN beneficial use assessment.

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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples exceeded the guideline for the COLD beneficial use assessment and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 100968, Azinphos-methyl (Guthion)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100498
 
Pollutant: Azinphos-methyl (Guthion)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 100968, Azinphos-methyl (Guthion)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100597
 
Pollutant: Azinphos-methyl (Guthion)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
100969
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Benefin
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of the 4 samples exceed the water quality guideline for the COLD beneficial use assessment, and 0 of 4 sample exceed the water quality guideline for the MUN beneficial use assessment.

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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples exceeded the guideline in either assessment and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 100969, Benefin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100598
 
Pollutant: Benefin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 100969, Benefin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100499
 
Pollutant: Benefin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
103518
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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 of evidence evaluating benthic-macroinvertebrate bioassessment data ais available in the administrative record to assess this indicator. 1 of 1 benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. However, a minimum of two benthic-macroinvertebrate samples are required to fully assess listing status.

Based on the readily available data and information, the weight of evidence indicates that there is insufficient information to justify 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. 1 of 1 benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. The available information is insufficient to justify placement of this waterbody/pollutant combination 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 Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 103518, Benthic Community Effects
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 96361
 
Pollutant: Benthic-Macroinvertebrate Bioassessments
LOE Subgroup: Population/Community Degradation
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
Aquatic Life Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: Benthic macroinvertebrate surveys
Data Used to Assess Water Quality: The site had a CSCI score of 0.467383958. These scores indicates that this site is not supporting aquatic life beneficial uses and that the water quality objective is not met.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP Perennial Stream Surveys.
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population or community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
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 (Rhen, 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: The California Stream Condition Index (CSCI): A New Statewide Biological Scoring Tool for Assessing the Health of Freshwater Streams.
 
Spatial Representation: Sample collected at site 633PS0142
Temporal Representation: Sample collected on 6/30/2014.
Environmental Conditions:
QAPP Information: QAPP for SWAMP Perennial Stream Surveys
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
78310
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Bifenthrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision and the attached LOE should be retired during the next cycle because they no longer are located in this segment due to re-segmentation of the WF Carson.

Text from past decision

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 78310, Bifenthrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43950
 
Pollutant: Bifenthrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Bifenthrin.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan for the Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The evaluation guideline for bifenthrin is the median lethal concentration (LC50) of 0.43 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.43 ug/g is the geometric mean of LC50 values for bifenthrin from Amweg et al. (2005) and Amweg and Weston (2007).
Guideline Reference: Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville - 633WCRSED]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
80102
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Boron
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff 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. 6 of the 38 samples exceed the water quality criteria.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 6 of 38 samples exceeded the criteria 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 Staff Decision Recommendation: After review of 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.
 
 
Line of Evidence (LOE) for Decision ID 80102, Boron
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100449
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 31
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected over a 31 year period. On 9 of those years, the annual average exceeded 0.02 mg/L.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The site-specific objective in Lahontan Basin Plan Table 3-14 is 0.02 mg/L (= 20 ug/L) as a mean of monthly means. The objective applies upstream from Woodfords under the Tributary Rule.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample collected at the following locations: SW-01-Carson River, W Fork, Crystal Springs Rd D-1-Carson River, West Fork @ Diversion
Temporal Representation: Samples collected between 7/8/1980 and 6/2/2010.
Environmental Conditions:
QAPP Information: South Tahoe Public Utility District Laboratory Quality Assurance Program (by Terry Powers, Laboratory Director). March 30, 2009.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 80102, Boron
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 96858
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Headwaters to Woodfords) to determine beneficial use support and results are as follows: 2 of 6 samples exceeded the water quality standard for Boron. The two exceedances were for 2014 and 2015.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The site specific objective in the Lahontan Basin Plan for boron for the West Form Carson River at Woodfords (table 3-14) is 0.02 mg/L mean of monthly means. This objective is applied as per the tributary rule as stated in Chapter 2 of the Basin Plan: "additional beneficial uses may apply to waters with in these categories under the tributary rule, which provides that water quality standards for specific waterbodies apply upstream to tributaries for which no site-specific standards have been adopted."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 2 monitoring site(s) (633WCR002, 633WFCB03)
Temporal Representation: The samples were collected between the dates of 2010-10-20 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
Line of Evidence (LOE) for Decision ID 80102, Boron
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 96859
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP RWB6 Monitoring data for Carson River, West Fork (Headwaters to Woodfords) to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality standard for Total Boron (0.151 mg/L).
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The site specific objective in the Lahontan Basin Plan for sulfate for the West Fork Carson River (table 3-14) is 0.02 mg/L mean of monthly means. This objective is applied as per the tributary rule as stated in Chapter 2 of the Basin Plan: "additional beneficial uses may apply to waters with in these categories under the tributary rule, which provides that water quality standards for specific waterbodies apply upstream to tributaries for which no site-specific standards have been adopted."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (633WFCB03)
Temporal Representation: The samples were collected between the dates of 2014-12-08 and 2014-12-08
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program  
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101005
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Butylate
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 Staff 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 are necessary to assess listing status.

Two lines of evidence, one evaluating data for the MUN beneficial use and evaluating data for the COLD beneficial use, are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality criteria.

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. 0 of 4 samples in either assessment exceeded the criteria and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101005, Butylate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100500
 
Pollutant: Butylate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101005, Butylate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100544
 
Pollutant: Butylate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79962
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Cadmium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision and the attached LOE should be retired during the next cycle because they are no longer located in this segment due to re-segmentation of the WF Carson.

Text from last cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79962, Cadmium
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 44061
 
Pollutant: Cadmium
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Cadmium.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for cadmium is 4.98 mg/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
101007
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Carbaryl
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 Staff 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.

Two lines of evidence, one each evaluating data for the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality criteria.

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. 0 of 4 samples in either assessment exceeded the criteria and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101007, Carbaryl
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100501
 
Pollutant: Carbaryl
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101007, Carbaryl
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100545
 
Pollutant: Carbaryl
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101008
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Carbofuran
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 Staff 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.

Two lines of evidence, one each evaluating the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality criteria.

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. 0 of 4 samples in either assessment exceeded the criteria and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101008, Carbofuran
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100548
 
Pollutant: Carbofuran
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101008, Carbofuran
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100502
 
Pollutant: Carbofuran
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79964
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Chlordane
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision and the attached LOE should be retired during the next cycle because they are no longer located in this segment due to re-segmentation of the WF Carson.

Text from last cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79964, Chlordane
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 33734
 
Pollutant: Chlordane
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Zero of 1 sample collected exceeded the criteria for chlordane concentration (Sum of trans-Chlordane, cis-Chlordane, cis-Nonachlor, trans-Nonachlor, and Oxychlordane).
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Water Quality Control Plan, Lahontan Region (2005): All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. Waters shall not contain substances in concentrations that result in deposition of material that causes nuisance or that adversely affects the water for beneficial uses.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The Probable Effect Concentration for Chlordane in freshwater sediments is 17.6 ug/kg.
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data were collected at the following station 633WCRSED (West Fork Carson River at Paynesville).
Temporal Representation: One sample was collected on 9/22/2008.
Environmental Conditions:
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
79965
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Chlorpyrifos
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff 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.

Two lines of evidence that are both based on the same dataset assessed for COLD and MUN are available in the administrative record to assess this pollutant. 0 of 4 water samples exceed the water quality criteria for the COLD and MUN beneficial uses.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 water samples exceeded the criteria for the COLD and MUN beneficial uses. These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 79965, Chlorpyrifos
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100503
 
Pollutant: Chlorpyrifos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79965, Chlorpyrifos
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100549
 
Pollutant: Chlorpyrifos
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79966
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Chromium
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision and the attached LOE should be retired during the next cycle because they are no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79966, Chromium
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 44100
 
Pollutant: Chromium
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Chromium.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for chromium is 111 mg/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
78896
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Copper
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision and the attached LOE should be retired during the next cycle because they are no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 78896, Copper
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43804
 
Pollutant: Copper
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Copper.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for copper is 149 mg/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
101009
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Cyanazine
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 Staff 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.

Two lines of evidence, one each evaluating data for the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of the samples exceed the water quality criteria.

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. 0 of 4 samples in either assessment exceeded the criteria and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101009, Cyanazine
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100552
 
Pollutant: Cyanazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101009, Cyanazine
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100504
 
Pollutant: Cyanazine
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
78938
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Cyfluthrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision and the attached LOE should be retired during the next cycle because they are no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle:

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 78938, Cyfluthrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43925
 
Pollutant: Cyfluthrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Cyfluthrin, total.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan for the Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The evaluation guideline for cyfluthrin is the median lethal concentration (LC50) of 1.1 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1.1 ug/g is the geometric mean of LC50 values for cyfluthrin from Amweg et al. (2005).
Guideline Reference: Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville - 633WCRSED]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
78939
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Cyhalothrin, Lambda
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 78939, Cyhalothrin, Lambda
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43885
 
Pollutant: Cyhalothrin, Lambda
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Cyhalothrin, lambda, total.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan for the Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The evaluation guideline for lambda-cyhalothrin is the median lethal concentration (LC50) of 0.44 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.44 ug/g is the geometric mean of LC50 values for lambda-cyhalothrin from Amweg et al. (2005).
Guideline Reference: Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville - 633WCRSED]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
79402
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Cypermethrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79402, Cypermethrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43915
 
Pollutant: Cypermethrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Cypermethrin, total.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan for the Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The evaluation guideline for cypermethrin is the median lethal concentration (LC50) of 0.3 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.3 ug/g is the geometric mean of LC50 values for cypermethrin from Maund et al. (2002).
Guideline Reference: Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville - 633WCRSED]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
101010
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
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 Staff 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.

Two lines of evidence, one each evaluating data for the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality criteria.

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. 0 of 4 samples in either assessment exceeded the criteria and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101010, DDE (Dichlorodiphenyldichloroethylene)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100505
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101010, DDE (Dichlorodiphenyldichloroethylene)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100553
 
Pollutant: DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101011
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Dacthal
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 Staff 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.

Two lines of evidence, one each evaluating the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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. 0 of 4 samples in either beneficial use assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101011, Dacthal
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100506
 
Pollutant: Dacthal
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101011, Dacthal
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100556
 
Pollutant: Dacthal
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
80065
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Deltamethrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle:

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 80065, Deltamethrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43945
 
Pollutant: Deltamethrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Deltamethrin.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan for the Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The evaluation guideline for deltamethrin is the median lethal concentration (LC50) of 0.79 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.79 ug/g is the geometric mean of LC50 values for deltamethrin from Amweg et al. (2005).
Guideline Reference: Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville - 633WCRSED]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
79403
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Diazinon
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant that both assess the same dataset for MUN and COLD. 0 of 4 water samples exceed the water quality criteria for the COLD beneficial use and 0 of 4 water samples exceed the criteria for the MUN beneficial use.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 water samples exceeded the criteria for the COLD and MUN beneficial uses and this does not exceed 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 Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 79403, Diazinon
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100507
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79403, Diazinon
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100557
 
Pollutant: Diazinon
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79404
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Dieldrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant that assess the same data for COLD and MUN. 0 of the 4 water samples exceed the water quality criteria for the COLD beneficial use and 0 of 4 water samples exceed the criteria for the MUN beneficial.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 water samples exceeded the criteria for the MUN and COLD beneficial uses and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use/pollutant combinations are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 79404, Dieldrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100559
 
Pollutant: Dieldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79404, Dieldrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100508
 
Pollutant: Dieldrin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101012
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence, one evaluating the MUN and one evaluating the COLD beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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. 0 of 4 samples in either assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101012, Disulfoton
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100560
 
Pollutant: Disulfoton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101012, Disulfoton
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100509
 
Pollutant: Disulfoton
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101014
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence, one evaluating the COLD and one evaluating the MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101014, Dyfonate (Fonofos or Fonophos)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100513
 
Pollutant: Dyfonate (Fonofos or Fonophos)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101014, Dyfonate (Fonofos or Fonophos)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100561
 
Pollutant: Dyfonate (Fonofos or Fonophos)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101015
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: EPTC (Eptam, s-ethyl dipropylthiocarbamate)
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 Staff 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.

Two lines of evidence, one evaluating the COLD beneficial use and one evaluating the MUN beneficial use are available in the administrative record to assess this pollutant. 0 of 4 samples in each assessment exceed the water quality guideline.

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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in each assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101015, EPTC (Eptam, s-ethyl dipropylthiocarbamate)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100514
 
Pollutant: EPTC (Eptam, s-ethyl dipropylthiocarbamate)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101015, EPTC (Eptam, s-ethyl dipropylthiocarbamate)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100562
 
Pollutant: EPTC (Eptam, s-ethyl dipropylthiocarbamate)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79518
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Electrical Conductivity
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

One line of evidence that assesses for the COLD beneficial use consisting of 341 samples also collected over a 31 year period, are available in the administrative record to assess this pollutant. 0 of the samples exceeded the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 341 samples evaluated for the COLD beneficial use exceeded the 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 Staff Decision Recommendation: After review of 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.
 
 
Line of Evidence (LOE) for Decision ID 79518, Electrical Conductivity
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100530
 
Pollutant: Electrical Conductivity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 341
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected over 31 years. Of the 341 samples collected, none measured above 900 uS/cm.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: Maximum Contaminant Levels for organic and inorganic chemicals. CCR
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample collected at the following locations: SW-01-Carson River, W Fork, Crystal Springs Rd D-1-Carson River, West Fork @ Diversion
Temporal Representation: Samples collected between 7/8/1980 and 6/2/2010.
Environmental Conditions:
QAPP Information: South Tahoe Public Utility District Laboratory Quality Assurance Program (by Terry Powers, Laboratory Director). March 30, 2009.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79762
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Endrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79762, Endrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43824
 
Pollutant: Endrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Endrin.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's water quality objective for toxicity states: all waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce determental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for endrin is 207 ug/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
79405
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Esfenvalerate/Fenvalerate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle:

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79405, Esfenvalerate/Fenvalerate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 44313
 
Pollutant: Esfenvalerate/Fenvalerate
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Esfenvalerate/Fenvalerate, total.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan for the Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The evaluation guideline for esfenvalerate/fenvalerate is the median lethal concentration (LC50) of 1.5 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1.5 ug/g is the geometric mean of LC50 values for esfenvalerate/fenvalerate from Amweg et al. (2005).
Guideline Reference: Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville - 633WCRSED]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
101017
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Ethalfluralin
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 Staff 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.

Two lines of evidence, one each evaluating the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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 do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101017, Ethalfluralin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100563
 
Pollutant: Ethalfluralin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101017, Ethalfluralin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100524
 
Pollutant: Ethalfluralin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101018
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence, one each to evaluate the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101018, Ethoprop
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100525
 
Pollutant: Ethoprop
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101018, Ethoprop
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100564
 
Pollutant: Ethoprop
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
80196
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Fenpropathrin
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from past cycle;

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 80196, Fenpropathrin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 44353
 
Pollutant: Fenpropathrin
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Fenpropathrin.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan for the Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: The evaluation guideline for fenpropathrin is the median lethal concentration (LC50) of 1 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1 ug/g is the geometric mean of LC50 values for fenpropathrin from Ding et al. ( 2011).
Guideline Reference: Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville - 633WCRSED]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
101019
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Fluoride
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 Staff 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.

One line of evidence is available in the administrative record to assess this pollutant. 0 of the 5 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 5 samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is fully supported using table 3.2.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101019, Fluoride
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 97181
 
Pollutant: Fluoride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
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 SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality standard for Fluoride.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for Fluoride incorporated by reference in the Water Quality Control Plan, Lahontan Region is 2 mg/L (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (633WFCB03)
Temporal Representation: The samples were collected between the dates of 2014-12-08 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
101020
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Hexachlorobenzene/ HCB
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of 4 samples exceed the water quality guideline for each of the COLD and MUN beneficial use assessments.

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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101020, Hexachlorobenzene/ HCB
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100535
 
Pollutant: Hexachlorobenzene/ HCB
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101020, Hexachlorobenzene/ HCB
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100567
 
Pollutant: Hexachlorobenzene/ HCB
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79406
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Lead
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle:

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79406, Lead
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43844
 
Pollutant: Lead
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Lead.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for lead is 128 mg/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
79407
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence, one each assessing water data for the COLD and MUN beneficial uses, are available in the administrative record to assess this pollutant. 0 of 4 water samples exceed the water quality objectives for the COLD and MUN beneficial uses.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 water samples exceeded the objectives for the MUN and COLD beneficial uses and these sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples per beneficial use assessed are needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 79407, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100536
 
Pollutant: Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79407, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100568
 
Pollutant: Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101021
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Linuron
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 Staff 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.

Two lines of evidence which evaluate data for the MUN and COLD beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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. 0 of 4 samples in either assessment exceeded the guidelines and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101021, Linuron
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100571
 
Pollutant: Linuron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101021, Linuron
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100446
 
Pollutant: Linuron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101022
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence, one evaluating data for the COLD beneficial use and one evaluating data for the MUN beneficial use are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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. 0 of 4 samples in either beneficial use assessment exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101022, Malathion
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100572
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101022, Malathion
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100447
 
Pollutant: Malathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79408
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Mercury
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous decision

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79408, Mercury
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43854
 
Pollutant: Mercury
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Mercury.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for mercury is 1.06 mg/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
79412
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Methyl Parathion
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant that are based on the same data assessed for MUN and COLD. 0 of 4 water samples assessed for the COLD and MUN beneficial uses exceed the water quality guidelines.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 water samples assessed for the COLD and MUN beneficial uses exceeded the guidelines and these sample sizes are insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples per beneficial use assessed are needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 79412, Methyl Parathion
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100459
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79412, Methyl Parathion
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100575
 
Pollutant: Methyl Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101023
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Metolachlor
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of 4 samples assessed for the COLD and MUN beneficial uses exceed the water quality guidelines.

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. 0 of 4 samples in both beneficial use assessments exceeded the guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101023, Metolachlor
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100576
 
Pollutant: Metolachlor
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101023, Metolachlor
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100460
 
Pollutant: Metolachlor
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101024
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Metribuzin
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of 4 samples assessed for both the COLD and MUN beneficial uses exceed the water quality guideline.

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. 0 of 4 samples in either beneficial use assessments exceeded the guidelines and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101024, Metribuzin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100579
 
Pollutant: Metribuzin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101024, Metribuzin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100470
 
Pollutant: Metribuzin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101025
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Molinate
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 Staff 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.

Two lines of evidence are available in the administrative record to assess this pollutant. 0 of 4 samples assessed for both the COLD and MUN beneficial uses exceed the water quality guidelines.

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 do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either beneficial use assessment exceeded the guidelines and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101025, Molinate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100471
 
Pollutant: Molinate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101025, Molinate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100580
 
Pollutant: Molinate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101026
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Napropamide
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 Staff 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.

Two lines of evidence, one which evaluates data for the COLD beneficial use and one which evaluates data for the MUN beneficial use are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guidelines.

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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either assessment exceeded the guidelines and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101026, Napropamide
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100583
 
Pollutant: Napropamide
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101026, Napropamide
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100479
 
Pollutant: Napropamide
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
80197
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Nickel
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle:

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 80197, Nickel
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 43864
 
Pollutant: Nickel
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed SWAMP data for Carson River, West Fork (Woodfords to Paynesville) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Nickel.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for nickel is 48.6 mg/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data for this line of evidence for Carson River, West Fork (Woodfords to Paynesville) was collected at 1 monitoring site [ West Fork Carson River at Paynesville]
Temporal Representation: Data was collected on a single day 9/22/2008.
Environmental Conditions: Staff is not aware of any special conditions that might affect interpretation of the data.
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
101027
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. 0 of the 5 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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 do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 5 samples exceeded the objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101027, Nitrate/Nitrite (Nitrite + Nitrate as N)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 97128
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
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 SWAMP RWB6 Monitoring data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality standard for Nitrate + Nitrite as N.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for the SWAMP RWB6 Monitoring (tissue and water).
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The California Maximum Contaminant Level for nitrate + nitrite (as N) that is incorporated by reference in the Water Quality Control Plan, Lahontan Region is 10.0 mg/L (Water Quality Control Plan, Lahontan Region).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (633WFCB03)
Temporal Representation: The samples were collected between the dates of 2014-12-08 and 2015-11-19
Environmental Conditions:
QAPP Information: Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
QAPP Information Reference(s): Quality Assurance Program Plan and Standard Operating Procedures for SWAMP program
 
 
DECISION ID
79519
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Nitrogen, Nitrite
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence for the COLD beneficial use consisting of 103 samples collected also over an 8 year period (2002-2010), is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of the 103 available samples exceeded the objective and this does not exceed 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 Staff Decision Recommendation: After review of 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.
 
 
Line of Evidence (LOE) for Decision ID 79519, Nitrogen, Nitrite
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100517
 
Pollutant: Nitrite as Nitrite NO2
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 103
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: None of 103 samples exceeded the water quality objective for nitrite.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The Water Quality Control Plan, Lahontan Basin, Objective for Municipal and Domestic Supply uses of inland surface waters states the following: waters shall not contain concentrations of inorganic chemicals in excess of the limits specified in California Code of Regulations, Title 22, Table 64431-A of section 64431 (Inorganic Chemicals). The maximum contaminant level listed in Table 64431-A for Nitrite as N is 1.0 mg/L.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at SW-01 Carson River, W Fork, Crystal Springs Rd.
Temporal Representation: Samples were collected from January 2002 to June 2010.
Environmental Conditions:
QAPP Information: Samples were collected by STPUD and analyzed using STPUD Laboratory quality assurance program.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
78797
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Oxygen, Dissolved
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence, consisting of 154 samples collected over a period of 31 years, are available in the administrative record to assess this pollutant. Two of 154 samples exceed the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. Two of 154 samples exceeded the 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 Staff Decision Recommendation: After review of 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.
 
 
Line of Evidence (LOE) for Decision ID 78797, Oxygen, Dissolved
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 129944
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 27
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Water Board staff assessed Alpine Watershed Group Monitoring Program data for Carson River, West Fork (Hope Valley to Woodfords) to determine beneficial use support and results are as follows: 0 of 27 samples exceeded the water quality standard for Oxygen, Dissolved.
Data Reference: Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for Alpine Watershed Group Monitoring Program.
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: For waters with the beneficial uses of COLD, COLD with SPWN, WARM, and WARM with SPWN, the minimum dissolved oxygen concentration shall not be less than that specified in Table 3-6. (Water Quality Control Plan, Lahontan Region)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: The samples were collected at 1 monitoring site(s) (WF-WDFD)
Temporal Representation: The samples were collected between the dates of 2010-09-11 and 2017-03-11
Environmental Conditions:
QAPP Information: Quality Assurance Project Plan for Alpine Watershed Group Volunteer Citizen Water Quality Monitoring Program
QAPP Information Reference(s): Quality Assurance Project Plan for Alpine Watershed Group Volunteer Citizen Water Quality Monitoring Program
 
Line of Evidence (LOE) for Decision ID 78797, Oxygen, Dissolved
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100453
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 127
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data were collected over 31 years. Of the 127 daily averaged samples collected, 2 had dissolved oxygen levels below 7.0 mg/L.
Data Reference: Data for temperature, nutrients, and bacteria in Heavenly Valley Creek (USFS boundary to Trout Creek) and various water bodies in Alpine County, Jul 1980-Jun. 2010
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: The applicable water quality objective from the Lahontan Basin Plan states: "The dissolved oxygen concentration shall not be depressed by more than 10 percent, below 80 percent saturation, or below 7.0 mg/L at any time, whichever is more restrictive." (Note: this is a watershed-specific narrative objective that differs from the regionwide objectives in Basin Plan Table 3-6.)
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Sample collected at the following locations: SW-01-Carson River, W Fork, Crystal Springs Rd D-1-Carson River, West Fork @ Diversion
Temporal Representation: Samples collected between 7/8/1980 and 6/2/2010.
Environmental Conditions:
QAPP Information: South Tahoe Public Utility District Laboratory Quality Assurance Program (by Terry Powers, Laboratory Director). March 30, 2009.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79462
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: PCBs (Polychlorinated biphenyls)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: NOTE: This decision should be retired during the next cycle because it is no longer located in this segment due to re-segmentation of the WF Carson.

Text from previous cycle

This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the sample exceeds the water quality objective.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of the sample exceeded the guideline and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples is needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: This region was not assessed this cycle. All decisions have been carried over from the previous cycle and remain the same.
 
 
Line of Evidence (LOE) for Decision ID 79462, PCBs (Polychlorinated biphenyls)
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 33261
 
Pollutant: PCBs (Polychlorinated biphenyls)
LOE Subgroup: Pollutant-Sediment
Matrix: Sediment
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Zero of 1 sample collected for Total PCBs exceeded the evaluation guideline.
Data Reference: Statewide Stream Pollution Trends Study 2008
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: Waters shall not contain substances in concentrations that result in deposition of material that causes nuisance or that adversely affects the water for beneficial uses (Lahontan Region Basin Plan).
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline: In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for total PCB is 676 ug/Kg dry weight (MacDonald et al. 2000).
Guideline Reference: Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31
 
Spatial Representation: Data were collected at the following station 633WCRSED (West Fork Carson River at Paynesville).
Temporal Representation: The samples were collected on 9/22/2008.
Environmental Conditions:
QAPP Information: The SWAMP QAPP (2008) was followed.
QAPP Information Reference(s): Surface Water Ambient Monitoring Program Quality Assurance Program Plan
 
 
DECISION ID
101028
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence, one evaluating data for the MUN beneficial use and one evaluating data for the COLD beneficial use are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guideline.

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. 0 of 4 samples in either beneficial use assessment exceeded the guidelines and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101028, Parathion
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100480
 
Pollutant: Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101028, Parathion
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100584
 
Pollutant: Parathion
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101029
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Pendimethalin
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 Staff 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.

Two lines of evidence, one which evaluates data for the COLD beneficial use and one which evaluates data for the MUN beneficial use are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guidelines.

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 do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either beneficial use assessment exceeded the guidelines and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101029, Pendimethalin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100587
 
Pollutant: Pendimethalin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101029, Pendimethalin
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100492
 
Pollutant: Pendimethalin
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
79461
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
Pollutant: Permethrin, total
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Staff Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Three lines of evidence that evaluate water data for the COLD and MUN beneficial uses are available in the administrative record to assess this pollutant. 0 of 4 water samples exceed the water quality objective for the COLD and MUN beneficial use assessments.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.

This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 water samples assessed for the MUN and COLD beneficial uses and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of 16 samples per beneficial use assessed are needed for application of table 3.1.
4. Pursuant to Section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 79461, Permethrin, total
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100588
 
Pollutant: Permethrin, total
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 79461, Permethrin, total
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100493
 
Pollutant: Permethrin, total
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available."
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
 
DECISION ID
101030
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
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 Staff 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.

Two lines of evidence, one which evaluates data for the COLD beneficial use and one which evaluates data for the MUN beneficial use are available in the administrative record to assess this pollutant. 0 of 4 samples in either assessment exceed the water quality guidelines.

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 do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. 0 of 4 samples in either beneficial use assessment exceeded the guidelines and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples per beneficial use assessed are needed to determine if a beneficial use is fully supported using table 3.1.
4. Pursuant to SECTION 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
Regional Board Staff Decision Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.
 
 
Line of Evidence (LOE) for Decision ID 101030, Phorate
Region 6     
Carson River, West Fork (Hope Valley to Woodfords)
 
LOE ID: 100591
 
Pollutant: Phorate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Not Recorded
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The California Department of Pesticide Regulation's online database includes data for the West Fork Carson River at Woodfords. These data were collected in May, June, July and August 1994 as part of the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) program.. Only one of the 46 listed pesticides (pebulate) was detected, in one of four samples. The concentration was reported as 0.0090 ug/L.
Data Reference: Department of Pesticide Regulation Database Records for the West Fork Carson River and Upper Truckee Rivers
 
SWAMP Data: Non-SWAMP
 
Water Quality Objective/Criterion: Documentation of water quality criteria for individual pollutants in Lines of Evidence for multipollutant datasets is not required, except for pollutants that exceed a standard or criterion. There are no state or federal water quality standards or criteria for pebulate, the only detectable pollutant in this dataset. The Lahontan Basin Plan includes a narrative water quality objective for pesticides in surface waters that provides that: "Pesticide concentrations, individually or collectively, shall not exceed the lowest detectable leves, using the most recent detection procedures available." For waters designated for the Municipal and Domestic Supply beneficial use, the water quality objective references the California Maximum Contaminant Levels (MCLs) for pesticides.
Objective/Criterion Reference: Water Quality Control Plan for the Lahontan Region (as amended)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, West Fork Carson River at Woodfords, was sampled.
Temporal Representation: Samples were collected on May 10, June 13, July 12, and August 8, 1994 and analyzed for the 46 listed pesticides.
Environmental Conditions: The West Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in the Carson Valley, transitional between Sierra and Great Basin ecological conditions. In addition to the Cold Freshwater Habitat beneficial use, the West Fork Carson River is designated for the Spawning, Reproduction, and Development Use. The Woodfords station was sampled as part of the USGS National Water Quality Assessment (NAWQA) study of the Carson River watershed in California and Nevada, as part of a larger study of the Truckee and Carson Rivers and Las Vegas Wash.. Woodfords is upstream of the portion of the watershed used for irrigated agriculture.
QAPP Information: The data meet USGS quality assurance requirements.
QAPP Information Reference(s): South Lake Tahoe Public Utility District Laboratory Quality Assurance Program
 
Line of Evidence (LOE) for Decision ID 101030, Phorate
Region 6