Final California 2010 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	Carson River, West Fork (Headwaters to Woodfords)
Water Body ID:	CAR6332001420000207111737
Water Body Type:	River & Stream


DECISION ID	6482	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Sodium
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2006)
Revision Status	Revised
Sources:	Nonpoint Source
Reason for Delisting:	Other
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This segment was placed on the 2002 Section 303(d) list for violation of the water quality objective for "Percent Sodium." Percent Sodium is the ratio of sodium ion concentration to the sum of the concentrations of calcium, magnesium and potassium ions. It is an older irrigation water criterion and is no longer widely used.The 2002 listing was for "Sodium" rather than "Percent Sodium" because "Sodium" was the only picklist choice available in the database in use at the time. In 2006 the Lahontan RWQCB adopted Basin Plan amendments to replace the water quality objectives for percent sodium for surface waters of the Carson and Walker River watersheds with new objectives for "Sodium Adsorption Ratio" (SAR). The amendments were approved by the SWRCB and the Office of Administrative Law in 2007 and by the USEPA, Region IX in 2008. . SAR is a ratio of sodium ion concentration to the concentrations of calcium and magnesium ions. It is calculated differently from Percent Sodium and the two types of objectives are NOT directly comparable. The SAR limits in the new objectives are compatible with current federal and international irrigation water quality criteria and with the State of Nevada's antidegradation- based SAR standards for state line stations. The new SAR limits are expressed as annual means, rather than means of monthly means. A single SAR objective for the West Fork Carson River in California has replaced the two objectives for Percent Sodium that were applicable to different segments of the river. The listing for sodium is being considered for removal from the section 303(d) list under section 4 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. The new SAR objective for the Headwaters to Woodfords segment of the West Fork Carson River has been attained in 19 out of 19 years. 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 section 303(d) list. This conclusion is based on the staff findings that: 1.The data used satisfy the data quality requirements of section 6.1.4 of the Listing Policy. 2. The data used satisfy the data quantity requirements of section 6.1.4 of the Listing Policy. 3. The new water quality objective was attained in 19 out of 19 years and this does not exceed the allowable frequency in Table 3.2 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 Decision Recommendation:	RWQCB staff concludes that the water body-pollutant combination should be removed from the Section 303(d) list because Basin Plan amendments deleting and replacing the water quality objective involved in the 2002 listing have been approved and are in effect and the applicable water quality standards for the pollutant are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 6482, Sodium	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

5375

Pollutant:

Sodium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

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):


DECISION ID	6480	Region 6
Carson River, West Fork (Headwaters 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)(2006)
Revision Status	Revised
Sources:	Atmospheric Deposition \| Channel Erosion \| Erosion/Siltation \| Habitat Modification \| Highway Maintenance and Runoff \| Natural Sources \| Onsite Wastewater Systems (Septic Tanks) \| Recreational and Tourism Activities (non-boating) \| Removal of Riparian Vegetation \| Silviculture \| Streambank Modification/Destabilization
Expected TMDL Completion Date:	2019
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the 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. Four lines of evidence are available in the administrative record to assess this pollutant. They include summaries of the data originally used for listing, and more recent data. The site-specific objectives (SSOs) are expressed as annual means of monthly means (MOMMs), which are long term running averages. The original listing was based on violations of the SSO by single MOMM datapoints for total Kjeldahl nitrogen and total nitrogen. Two of 3 MOMM datapoints for total Kjeldahl nitrogen and 1 of 3 MOMM datapoints for total nitrogen exceeded the applicable SSOs. At least 26 MOMM datapoints, with fewer than 2 exceedances, would be required to delist using Table 4.1 of the Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfy 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. Quarterly samples do not capture the full range of seasonal and annual variation in streamflows and constituent concentrations expected in stream of the Lahontan Region. 3. The original listing involved exceedance of the applicable SSOs by single MOMMs for each constituent. In the more recent dataset 2 of 3 MOMM datapoints exceeded the SSO for total Kjeldahl nitrogen and 1 of 4 MOMM datapoints exceeded the SSO for total nitrogen. 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 Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):	USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.

Line of Evidence (LOE) for Decision ID 6480, Nitrogen	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27605

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The USGS sampled this station under the Region 6 SWAMP program between 2003 and 2005. Total Nitrogen was calculated from reported results for total Kjeldahl nitrogen and nitrite plus nitrate. Calculated total N concentrations in 10 quarterly samples ranged from 0.046 to 0.204 mg/L. Calculated means of monthly means were as follows: for 2003, 0.132 mg/L; for 2004, 0.146 mg/L; for 2005, 0.176 mg/L.

Data Reference:

Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled..

Temporal Representation:

Quarterly samples (3 to 4 per year) were collected between April 2003 and August 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6480, Nitrogen	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27603

Pollutant:

Total Kjeldahl Nitrogen (TKN)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The USGS sampled this station under the Region 6 SWAMP program between 2003 and 2005. Concentrations of TKN in 10 samples ranged from 0.04 to 0.19 mg/L. Calculated means of monthly means were as follows: for 2003, 0.11 mg/L; for 2004, 0.15 mg/L; for 2005, 0.18 mg/L.

Data Reference:

Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The water quality objective for total Kjeldahl nitrogen in this segment is 0.13 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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Samples were collected quarterly (3 to 4 per year) between April 2003 and August 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6480, Nitrogen	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27602

Pollutant:

Total Kjeldahl Nitrogen (TKN)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

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 Kjeldahl 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 Kjeldahl nitrogen in this segment is 0.13 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:

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):

Line of Evidence (LOE) for Decision ID 6480, Nitrogen	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27599

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

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:

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):


DECISION ID	6481	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Phosphorus
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)(2006)
Revision Status	Revised
Sources:	Atmospheric Deposition \| Channel Erosion \| Erosion/Siltation \| Habitat Modification \| Highway Maintenance and Runoff \| Natural Sources \| Recreational and Tourism Activities (non-boating) \| Removal of Riparian Vegetation \| Silviculture \| Streambank Modification/Destabilization
Expected TMDL Completion Date:	2019
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the 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 this pollutant. In the dataset used for the original listing, 3 of 4 annual "mean of monthly means" (MOMM) datapoints exceeded the site-specific water quality objective (SSO). In a more recent dataset, 1 of 3 MOMM datapoints exceeded the SSO. Under Table 4.1 of the Policy, at least 26 MOMM datapoints with fewer than 2 exceedances would be required for delisting. (There is a quality assurance problem with the more recent data.) Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The dataset originally used for listing satisfies the quality assurance requirements of section 6.1.4 of the Listing Policy. The more recent dataset does not satisfy the data quality requirements of section 6.1.4 of the Policy due to an error in the SWAMP QAPP regarding holding times for total phosphorus samples. 2. The recent dataset used does not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of seasonal and annual variation expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Three of 4 MOMM datapoints used in the original listing and 1 of 3 MOMM datapoints in a more recent dataset exceeded the SSO 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 Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):	USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.

Line of Evidence (LOE) for Decision ID 6481, Phosphorus	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27595

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled the West Fork Carson River between 2003 and 2005 under the Region 6 SWAMP program. Concentrations of total phosphorus in 10 samples ranged from 0.012 to 0.061 mg/L. Calculated means of monthly means were as follows: 2003, 0.012 mg/L; 2004, 0.018 mg/L, and 2005, 0.022 mg/L.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The water quality objective for total phosphorus in thiis 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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Quarterly samples (3 or 4 per year) were collected between April 2003 and August 2005.

Environmental Conditions:

QAPP Information:

Sampling and analysis were done according to the SWAMP QAPP. However, in July 2009 an error was discovered in the QAPP related to holding times for total phosphorus samples that affects the validity of data for the Lahontan Region The holding time for samples that are not acid-preserved.should be 48 hours rather than 28 days as indicated in the QAPP. "Low level" phosphorus analyses, without acid preservation, are used in the Lahontan Region's SWAMP program. ..

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6481, Phosphorus	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27592

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

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 means of monthly means during the assessment period beginning in 1997 were as follows: 1997, 0.09 mg/L; 1998, 0.03 mg/L, 1999, 0.02 mg/L, 2000, 0.03 mg/L.

Data Reference:

Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The water quality objective for total phosphorus in thiis 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:

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):


DECISION ID	16191	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	2, 6- diethylaniline \| 2-chloro-4-isopropylamino-6-amino-s-triazine \| Alachlor \| Atrazine \| Azinphos-methyl (Guthion) \| Benefin \| Butylate \| Carbaryl \| Carbofuran \| Chlorpyrifos \| Cyanazine \| DDE (Dichlorodiphenyldichloroethylene) \| Dacthal \| Diazinon \| Dieldrin \| Disulfoton \| Dyfonate (Fonofos or Fonophos) \| EPTC (Eptam, s-ethyl dipropylthiocarbamate) \| Ethalfluralin \| Ethoprop \| Hexachlorobenzene/ HCB \| Lindane/gamma Hexachlorocyclohexane (gamma-HCH) \| Linuron \| Malathion \| Methyl Parathion \| Metolachlor \| Metribuzin \| Molinate \| Napropamide \| Parathion \| Pendimethalin \| Permethrin, total \| Phorate \| Prometon (Prometone) \| Pronamide \| Propachlor \| Propanil (DCPA mono- and di-acid degrad) \| Propargite \| Simazine \| Tebuthiuron \| Terbacil \| Terbufos \| Thiobencarb/Bolero \| Triallate \| Trifluralin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	These pollutants are 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. Samples were analyzed for 46 pesticides, and 45 of these were not detected. 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 satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not the data quantity requirements of section 6.1.5 of the Policy. Samples were collected during four consecutive months and did not represent seasonal and annual variation. Sampling was done in 1994 and is not necessarily representative of current conditions in the watershed. 3. Four samples were analyzed for 46 pesticides; 45 of these were not detectable. Under the Section 6.1.5.5 of the Listing Policy, applicable standards and criteria for the nondetectable pesticides are considered to be attained. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 16191, Multiple Pollutants	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

26846

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

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):

Line of Evidence (LOE) for Decision ID 16191, Multiple Pollutants	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

26739

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

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:

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:

QAPP Information:

The data meet USGS quality assurance requirements.

QAPP Information Reference(s):


DECISION ID	7714	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Arsenic
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	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. The single sample did not exceed the California Toxics Rule aquatic life standards or the California Maximum Contaminant Level. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The single sample used does not satisfy the data quantity requirements of section 6.1.5 or Table 3.1 of the Policy. 3. The single sample does not exceed either of the applicable standards 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 Decision Recommendation:	After review of 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 it cannot be determined if applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7714, Arsenic	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4860

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled arsenic in the West Fork Carson River under the Region 6 SWAMP program. One sample had an arsenic concentration of 0.6 ug/L. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The state MCL for arsenic is 10 ug/L (effective November 28, 2008).

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 below Willow Creek, was sampled.

Temporal Representation:

One sample was collected on 11/24/2004.

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 7714, Arsenic	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4861

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled arsenic in the West Fork Carson River under the Region 6 SWAMP program. One sample had an arsenic concentration of 0.6 ug/L. The California Toxics Rule standards were not exceeded.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule standards for protection of freshwater aquatic life are:
4-day average = 150 ug/L
1-hour average = 340 ug/L

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 below Willow Creek, was sampled.

Temporal Representation:

One sample was collected on 11/24/2004..

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	7715	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Boron
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	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. None of the samples exceeds the California State Notification Level or the site-specific water quality objective. Four samples were estimates and four were below the detection level The means of monthly means are assumed to be zero values. 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 satisfy 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. Quarterly samples do not capture the seasonal and annual variabiliy expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 3 "mean of monthly mean" datapoints exceeded either of the applicable standards 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 Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7715, Boron	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4862

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled boron in the West Fork Carson River under the Region 6 SWAMP program. Boron concentrations in 4 of 8 samples were estimates and the remaining 4 samples were below the detection level. Means of monthly means are assumed to be zero. The objective was not exceeded.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Eight samples were collected between 2002 and 2005.

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. The
"below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 7715, Boron	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

21501

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled boron in the West Fork Carson River under the Region 6 SWAMP program. Boron concentrations in 4 of 8 samples were estimates and the remaining 4 samples were below the detection level. The California State Notification Level was not exceeded.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California State Notification Level for boron is 1000 ug/L.

Objective/Criterion Reference:

Water Quality Control Plan for the Lahontan Region (as amended)

Drinking Water Notification and Response Levels: An Overview

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Eight samples were collected between 2002 and 2005.

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. The
"below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	7808	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Chloride
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. The site-specific water quality objective, expressed as a "mean of monthly means" was exceeded in three out of three years. 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 satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability in streamflows and constituent concentratiosn expected in streams of the Lahontan Region. 3. Three of three annual "mean of monthly means" datapoints exceeded the site specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the minimum sample number requirements of Table 3.2 of the Listing Policy are not met.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7808, Chloride	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4864

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled chloride in the West Fork Carson River under the Region 6 SWAMP program. Chloride concentrations in 10 samples ranged from 0.54 to 3.02 mg/L. The mean of monthly means objective, calculated beginning in 2003, was exceeded in 3 of 3 years.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Ten samples were collected between 2002 and 2005. Means of monthly means were calculated for each of three years.

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 7808, Chloride	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4866

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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 chloride is 250 mg/L.

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 below Willow Creek, was sampled.

Temporal Representation:

Ten samples were collected between 2002 and 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	7711	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Dissolved oxygen saturation
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 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. None of the samples 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 satisfy 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. Quarterly samples do not capture the diel, seasonal and annual variations expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. None of seven samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7711, Dissolved oxygen saturation	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

5727

Pollutant:

Dissolved oxygen saturation

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey measured dissolved oxygen in the West Fork Carson River under the Region 6 SWAMP program. Percent saturation in 7 quarterly samples taken between February 2004 and August 2005 ranged from 93 to 124 percent. The objective was not violated.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The applicable 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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Seven quarterly measurements of percent saturation were taken between February 2004 and August 2005.

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	10594	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Fecal Coliform
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy 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. Quarterly samples do not capture the seasonal and annual variation expected in streamflows and fecal coliform counts in streams of the Lahontan Region. The water quality objective calls for collection of 5 samples within 30 days 3. One of 7 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 10594, Fecal Coliform	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

5891

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Water column surveys (e.g. fecal coliform)

Data Used to Assess Water Quality:

The U.S. Geological Survey took quarterly samples under the Region 6 SWAMP program between November 2003 and May 2005. Counts of fecal coliform bacteria in seven samples included two samples below the detection level, four estimated values, and one count of 48 colonies per 100 mL. The last sample violated the objective.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's objective for:coliform bacteria states:

"Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste.

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. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."

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 below Willow Creek, was sampled.

Temporal Representation:

Seven quarterly samples for fecal coliform were taken between November 2003 and May 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 10594, Fecal Coliform	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

5889

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Water column surveys (e.g. fecal coliform)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's objective for coliform bacteria states:

"Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste.

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. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."

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 below Willow Creek, was sampled.

Temporal Representation:

Seven quarterly samples for fecal coliform were taken between November 2003 and May 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	16413	Region 6
Carson River, West Fork (Headwaters 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 Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy 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. Quarterly samples do not capture the full range of seasonal and annual variation in streamflows and constituent concentrations expected in streams of the Lahontan Region. 3. None of 4 samples exceeded the California Maximum Contaminant Level 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 Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 16413, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27607

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The USGS sampled this station under the Region 6 SWAMP program between 2003 and 2005. Concentrations of nitrite plus nitrate in 10 samples ranged from below the detection level to 0.084 mg/L. The MCL was not exceeded.

Data Reference:

Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002

SWAMP Data:

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 nitrite plus nitrate is 10 mg/L.

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 below Willow Creek, was sampled.

Temporal Representation:

Quarterly samples were collected between April 2003 and August 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	16414	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Nitrite as Nitrite NO2
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). 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 satisfy 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. Quarterly samples do not capture the full range of seasonal and annual variability expected in streamflows and constituent concenrations in streams of the Lahontan Region. 3. None of 4 samples exceeded the MCL 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 Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 16414, Nitrite as Nitrite NO2	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27606

Pollutant:

Nitrite as Nitrite NO2

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The USGS sampled this station under the Region 6 SWAMP program between 2003 and 2005. Four samples for nitrite were all below the detection level. The MCL was not exceeded.

Data Reference:

Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002

SWAMP Data:

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 nitrite is 1 mg/L.

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 below Willow Creek, was sampled.

Temporal Representation:

Four samples were collected in April, August, and November 2003 and in August 2004.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7712	Region 6
Carson River, West Fork (Headwaters 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:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 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. 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 satisfy 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. Quarterly samples do not capture the diel, seasonal and annual variability in streamflows and dissolved oxygen concentrations in the Lahontan Region. 3. None of ten samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7712, Oxygen, Dissolved	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4879

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey measured dissolved oxygen in the West Fork Carson River under the Region 6 SWAMP program. Dissolved oxygen concentrations in 10 samples ranged from 8 to 12.2 mg/L.. The objective was not violated.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Ten quarterly dissolved oxygen samples were taken between 2003 and 2005.

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	16235	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Pebulate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One of the samples 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 satisfy 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. Samples were collected only in the spring and summer. 3. One of four samples exceeded the water quality 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 Decision Recommendation:	After review of 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 it cannot be determined if applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 16235, Pebulate	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27046

Pollutant:

Pebulate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The California Department of Pesticide Regulation database contains data from the USGS National Water Quality Assessment (NAWQA) program. Four samples were collected in May, June, July and August 1994. Pebulate was detected in one sample collected June 13, 1994, at a concentration of 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:

There are no specific state or federal standards or criteria for pebulate. 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 below Willow Creek, was sampled.

Temporal Representation:

Samples were collected in May, June, July an August 1994.

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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:

USGS quality assurance procedures were used.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 16235, Pebulate	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27045

Pollutant:

Pebulate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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 below Willow Creek, was sampled.

Temporal Representation:

Samples were collected in May, June, July an August 1994.

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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:

USGS quality assurance procedures were used.

QAPP Information Reference(s):


DECISION ID	7786	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Sediment
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The Lahontan Basin Plan's narrative water quality objective is an antidegradation based objective that provides that there shall be no increases in suspended sediment concentrations or loads. This pollutant is being considered for placement on the section 303(d) list under section 3.10 of the Listing Policy, which deals with trends in water quality. One line of evidence, based on quarterly sampling, is available in the administrative record to assess this pollutant. It includes 10 suspended sediment concentration values and 8 suspended sediment load values calculated from instantaneous discharge measurements. Suspended sediment concentrations and loads are dependent on flows and can change rapidly over a short time during storm or snowmelt runoff events. Quarterly samples are insufficient to capture these short term events and therefore are insufficient to define natural background suspended sediment concentrations and loads, or to detect trends. Listing Policy Section 3.10 requires that natural background conditions be established. 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 satisfy 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. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and suspended sediment concentrations in the Lahontan Region. 2. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy Section 3.10. 3. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because available information and data do not meet the requirements of Listing Policy section 3.10.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7786, Sediment	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4883

Pollutant:

Sediment

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled suspended sediment in the West Fork Carson River under the Region 6 SWAMP program and calculated sediment loads with concurrent flow data. Instantaneous discharge flows ranged from 7.3 to 549 cfs. The highest flow was measured during spring runoff season in May 2005. Suspended sediment concentrations in 10 samples ranged from 1 to 32 mg/L. Suspended sediment loads in 8 calculations ranged from 0.06 to 47 tons per day.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The objective in the Lahontan Basin Plan states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."

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 below Willow Creek, was sampled.

Temporal Representation:

Ten samples were collected between 2003 and 2005 and 8 loading calculations were done.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	7713	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Specific Conductance
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 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. 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 satisfy 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. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and dissolved ion concentrations in streams of the Lahntan Region. 3. None of ten samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7713, Specific Conductance	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4882

Pollutant:

Specific Conductance

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey measured specific conductance in the West Fork Carson River under the Region 6 SWAMP program. Ten field measurements ranged from 36 to 80 uS/cm. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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:

Water Quality Control Plan for the Lahontan Region (as amended)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Ten field measurements were collected between 2003 and 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	7809	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Sulfates
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level. Three of the "mean of monthly means" datapoinits exceed the site-specific 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 satisfy 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. Quarterly samples do not capture the seasonal and annual variability in streamflows and constituent concentrations expected in streams of the Lahontan Region. 3. None of 10 samples exceeded the California Maximum Contaminant Level. Three of three "mean of monthly means" datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7809, Sulfates	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4885

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled suspended sediment in the West Fork Carson River under the Region 6 SWAMP program. Sulfate concentrations in 10 samples ranged from 0.8 to 3.8 mg/L. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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 sulfate is 250 mg/L.

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 below Willow Creek, was sampled.

Temporal Representation:

Ten samples were collected between 2003 and 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 7809, Sulfates	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4884

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled the West Fork Carson River under the Region 6 SWAMP program between 2003 and 2005. Sulfate concentrations in 10 samples ranged from 0.8 to 3.8 mg/L. The annual mean of monthly means, calculated for each year from 2003 to 2005, exceeded the objective in each year (the highest value was 2.44 mg/L in 2003).

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Ten quarterly samples were collected between 2003 and 2005 and means of monthly means were computed for three years.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	7757	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Temperature, water
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The Lahontan Basin Plan's narrative temperature objective is an antidegradation-based objective that requires that there be no change in temperature in waters designated for the Cold Freshwater Habitat (COLD) beneficial use. The objective does not include specific numerical limits for protection of the COLD use. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough temperature samples to establish baseline conditions (including diel, seasonal, annual and interannual variations in temperature) or to detect declining trends in the temperature regime if such trends exist. Because temperature samples were collected only quarterly, weekly and monthly average data are not available for comparison with guidelines in the scientific literature for the temperature requirements of sensitive aquatic species such as salmonids, as directed in Listing Policy Section 6.1.5.9.

Regional Board Decision Recommendation:	After review of 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 available data are insufficient for assessment under Listing Policy Sections 3.10 and 6.1.5.9.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7757, Temperature, water	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

5885

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled temperature quarterly under the Region 6 SWAMP program between April 2003 and August 2005. Temperature in 10 measurements ranged from 0 to 16.5 degrees Celsius. .

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The temperature objective in the Lahontan Basin Plan states: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses.

For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered.

Temperature objectives for COLD interstate waters and WARM interstate waters are as specified in the 'Water Quality Control Plan for Control of Temperature in The Coastal and Interstate Waters and Enclosed Bays and Estuaries of California' including any revisions."

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 below Willow Creek, was sampled.

Temporal Representation:

Ten quarterly water temperature measurements were taken between April 2003 and August 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	7810	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Total Dissolved Solids
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level. One of the "mean of monthly means" datapoints 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 satisfy 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. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 10 samples exceeded the California Maximum Contaminant Level. One of three "mean of monthly means" datapoints exceeded the site-specific objective, and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 7810, Total Dissolved Solids	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4887

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled chloride in the West Fork Carson River under the Region 6 SWAMP program. TDS concentrations in 10 samples ranged from 35 to 71 mg/L. The annual mean of monthly means, calculated for each year from 2003 to 2005, exceeded the objective in one out of 3 years (the highest value was 57.5 mg/L in 2004).

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Ten samples were collected between 2002 and 2005. Annual means of monthly means were calculated for a three year period.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 7810, Total Dissolved Solids	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4886

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled TDS in the West Fork Carson River under the Region 6 SWAMP program. TDS concentrations in 10 quarterly samples collected between 2003 and 2005 ranged from 35 to 71 mg/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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 Total Dissolved Solids is 500 mg/L.

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 below Willow Creek, was sampled.

Temporal Representation:

Ten quarterly samples were collected between 2002 and 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	16180	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Turbidity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. There are no applicable standards or criteria for turbidity expressed as NTRU. Two of the samples expressed as NTU exceed the California Maximum Contaminant Level. The narrative water quality objective used to assess the COLD use is antidegradation- based, and there are insufficient samples to establish baseline and trend conditions to determine compliance under Section 3.10 of the Listing Policy. 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 satisfy 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.Quarterly samples do not capture the diel, seasonal and annual variability in streamflows and turbidity in streams of the Lahontan Region. 3. Two of 6 samples exceeded the California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Sample numbers were insufficient to determine compliance with the narrative water quality objective under Section 3.10 of the Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 16180, Turbidity	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

21504

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under of the Region 6 SWAMP program.between 2004 and 2005. Three of 4 field turbidity measurements expressed as NTRU were below the detection level. The fourth sample had a turbidity of 8.4 NTRU.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for turbidity expressed as NTRU for the protection of human health.

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 below Willow Creek, was sampled.

Temporal Representation:

Four field turbidity measurements expressed as NTRU were taken in 2004 and 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 16180, Turbidity	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

21503

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under of the Region 6 SWAMP program.between 2003 and 2004. Two of 6 field turbidity measurements expressed as NTU were below the detection level. The other samples ranged from 2 to 31 NTU. Two samples exceeded the MCL.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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 turbidity is 5 NTU.

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 below Willow Creek, was sampled.

Temporal Representation:

Six field turbidity measurements expressed as NTU were taken in 2003 and 2004.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 16180, Turbidity	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

21502

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for turbidity expressed as NTRU for the protection of aquatic life.

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 below Willow Creek, was sampled.

Temporal Representation:

Four field turbidity measurements expressed as NTRU were taken in 2004 and 2005.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 16180, Turbidity	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4888

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Six field turbidity measurements expressed as NTU were taken in 2003 and 2004.

Environmental Conditions:

QAPP Information:

The quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	10608	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The Lahontan Basin Plan's narrative pH objective for this watershed is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.

Regional Board Decision Recommendation:	After review of 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 it cannot be determined if applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 10608, pH	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

4881

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey measured pH in the West Fork Carson River under the Region 6 SWAMP program. The pH values in 10 samples collected from 2003 to 2005 ranged from 6.9 to 7.9 units.

Data Reference:

2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The applicable objective states: "Changes in normal ambient pH levels shall not exceed 0.5 unit." This is a watershed-specific objective, different from the Lahontan Basin Plan's regionwide objective .

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 below Willow Creek, was sampled.

Temporal Representation:

Ten pH measurements were taken between 2003 and 2005. .

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. The "below Willow Creek" station is in Hope Valley near the headwaters. 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 quality assurance requirements of the SWAMP QAPP were met.

QAPP Information Reference(s):


DECISION ID	16264	Region 6
Carson River, West Fork (Headwaters to Woodfords)

Pollutant:	Nitrate
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Source Unknown
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This segment was listed for "Nitrogen" in 2002 based on violations of site-specific objectives (SSOs) for total nitrogen, total Kjeldahl nitrogen and nitrate. For the 2008 assessment cycle, SWRCB staff requested preparation of a separate decision for nitrate. 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. The SSO for nitrate is an annual mean of monthly means, a running average based on historical data. Two lines of evidence are available in the administrative record to assess this pollutant. The 2002 listing for nitrogen involved one MOMM for nitrate in violation of the objective. MOMMs for nitrate from the 2003-2005 Region 6 SWAMP data violated the objective in 2 of 3 years. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy 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. Quarterly samples do not capture the full range of seasonal and annual variation in streamflows and constituent concentrations expected in streams of the Lahontan Region. 3. The single MOMM datapoint used in the original listing exceeded the SSO. Two out of three MOMM datapoints from a more recent dataset exceed the SSO and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):	USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.

Line of Evidence (LOE) for Decision ID 16264, Nitrate	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27604

Pollutant:

Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The USGS sampled this station under the Region 6 SWAMP program between 2003 and 2005. Data were collected for nitrate plus nitrite (as N). A smaller number of samples collected for nitrite alone were all below the detection level. Assuming the nitrate plus nitrite concentrations to be representative of nitrate, concentrations in 10 samples ranged from below the detection level (one sample) to 0.084 mg/L. Calculated means of monthly means for nitrate were as follows: for 2003, 0.019 mg/L; for 2004, 0.023 mg/L, and for 2005, 0.027 mg/L.

Data Reference:

Administrative Record of Lahontan RWQCB's 2001-2002 Section 303(d) List Update Process Resolution R6T-2002-0002

SWAMP Data:

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:

One station, West Fork Carson River below Willow Creek, was sampled.

Temporal Representation:

Quarterly samples (3 to 4 per year) were collected between April 2003 and August 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 16264, Nitrate	Region 6
Carson River, West Fork (Headwaters to Woodfords)

LOE ID:

27601

Pollutant:

Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

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:

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):