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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	East Walker River, below Bridgeport Reservoir
Water Body ID:	CAR6301001020011204100242
Water Body Type:	River & Stream


DECISION ID	6538	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Nitrogen
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
Reason for Delisting:	Flaws in original listing
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. Three lines of evidence are available in the administrative record to assess this pollutant. One line of evidence documents the data used in the original listing. This listing used a water quality objective that applies upstream of the station where data were collected. The applicable California water quality objective for the segment of the East Walker River downstream of Bridgeport Reservoir is the narrative objective for biostimulatory substances. No biological data are available to assess whether the data used for listing or the later SWAMP samples comply with this objective. 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 Policy. Both datasets were collected and analyzed by the USGS. 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. Water quality in this segment is also affected by the timing of releases from Bridgeport Reservoir. 3.The original listing was on the basis of one annual average datapoint in violation of a water quality objective that does not actually apply to this segment. No biological data are available to assess whether the nine monthly samples involved in the original listing, the 16 SWAMP samples for total Kjeldahl nitrogen and/or the 16 SWAMP samples for total nitrogen comply with the narrative objective for biostimulatory substances. The total number of samples available meets the minimum sample number requirement for delisting in Table 4.1 of the 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 be removed from the section 303(d) list because the original listing was based on erroneous application of a water quality objective and it cannot be determined whether the narrative objective applicable to this segment is 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 6538, Nitrogen	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

27682

Pollutant:

Nitrogen

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:

Nine samples collected by the U.S. Geological Survey in 2000 and 2001 had a mean concentration of 0.64 mg/L, exceeding the objective. The range of concentrations was 0.109 to 1.32 mg/L.

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 site-specific objective for Total Nitrogen includes an annual average of 0.50 mg/L and a 90th percentile value of 0.80 mg/L (Lahontan Basin Plan Table 3-15). (Note: this objective was used in the original listing. However, it applies to the East Walker River above Bridgeport Reservoir. There is no California numeric objective for nitrogen in the river below the reservoir.)

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at the USGS gaging station below Bridgeport Reservoir.

Temporal Representation:

Nine samples were collected approximately monthly in 2000 and 2001.

Environmental Conditions:

The East Walker River is an interstate river, influenced by geothermal springs, agricultural and highway drainage, and releases from Bridgeport Reservoir. Headwater streams originate near the Sierra Nevada crest. The state line is in an area transitional to Great Basin environmental conditions. The segment of the river between Bridgeport Reservoir and the state line supports a trophy brown trout fishery. In addition to the Cold Freshwater Habitat beneficial use, the East Walker River is designated for the Spawning, Reproduction and Development use and the Rare, Threatened or Endangered Species use. The latter designation reflects the watersheds role as habitat for the threatened Lahontan cutthroat trout.

QAPP Information:

The data were collected and analyzed under USGS quality assurance protocols.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6538, Nitrogen	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7749

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 U.S. Geological Survey collected 16 quarterly samples under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total Kjeldahl nitrogen ranged from 0.37 to 3.1 mg/L. No associated data on algae or macrophytes were available for assessment of compliance with the objective for biostimulatory substances.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There is no site-specific objective for total Kjeldahl nitrogen. The Lahontan Basin Plan's narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Sixteen quarterly samples were collected between 2001 and 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 6538, Nitrogen	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5036

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 U.S. Geological survey sampled this segment under the Region 6 SWAMP program, at quarterly intervals between 2001 and 2005. Calculated concentrations of total nitrogen in 16 samples ranged from 0.386 to 3.463 mg/L. No biologiical data were collected for assessment of compliance with the objective for biostimulatory substances.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There is no site-specific numerical objective in the Lahontan Basin Plan for Total Nitrogen for this segment. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Sixteen quarterly samples (two to four samples per year) were collected between 2001 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	6539	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Phosphorus
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
Reason for Delisting:	Flaws in original listing
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. One line of evidence documents the data used in the original listing. This listing used a water quality objective that applies upstream of the station where data were collected. The applicable California water quality objective for the segment of the East Walker River downstream of Bridgeport Reservoir is the narrative objective for biostimulatory substances. No biological data are available to assess whether the data used for listing or the later SWAMP samples comply with this objective. 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 SWAMP data used do 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 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. Water quality in this segment is also affected by the timing of releases from Bridgeport Reservoir. 3. The original listing was on the basis of one annual average datapoint in violation of a water quality objective that does not actually apply to this segment. No biological data are available to assess whether the 11 monthly samples involved in the original listing or the 15 quarterly SWAMP samples for total phosphorus comply with the narrative objective for biostimulatory substances. The data cannot be assessed using Table 4.1 of the 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 be removed from the section 303(d) list because the original listing was flawed and there is insufficient information to determine whether the applicable water quality objective for the pollutant is 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 6539, Phosphorus	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

27683

Pollutant:

Phosphorus

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 U.S. Geological Survey collected monthly samples at the gaging station below Bridgeport Reservoir between April 2000 and February 2001. The mean concentrations of these 11 samples was 0.083 mg/L. The mean annual cocentration in nine USGS samples for 2000 was 0.094 mg/L.

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 site-specific water quality objective used in the 2002 listing of the East Walker River included an annual mean total phosphorus concentration of 0.06 mg/L and a 90th percentile value of 0.10 mg/L. This objective actually applies to a station upstream of Bridgeport Reservoir.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at the USGS gaging station below Bridgeport Reservoir.

Temporal Representation:

Eleven samples were collected monthly between April 2000 and February 2001.

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 6539, Phosphorus	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5049

Pollutant:

Phosphorus

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 U.S. Geological survey sampled the East Walker River under the Region 6 SWAMP program, at quarterly intervals between 2001 and 2005. Concentrations of total P in 15 samples ranged from 0.036 to 0.37 mg/L. No biological data are available for assessment of compliance with the objective for biostimulatory substances.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no site specific numerical objectives for phosphorus for this segment. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Fifteen quarterly samples were taken between 2001 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	6540	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Sedimentation/Siltation
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:	Erosion/Siltation \| Grazing-Related Sources \| Highway Maintenance and Runoff \| Upstream Impoundment \| Urban Runoff--Erosion and Sedimentation
Expected TMDL Completion Date:	2019
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Two lines of evidence are available in the administrative record to assess this pollutant. The original listing was based on best professional judgment regarding a single severe sedimentation incident. Water Board staff did not review quantitative data in connection with the listing. The applicable narrative water quality objective is antidegradation based. The 16 quarterly SWAMP samples are insufficient to establish baseline and trend conditions as required for assessment under Section 4.10 of the Listing 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 variability in streamflows and constituent concentrations expected in streams of the Lahontan Region. Flows and concentrations in this segment are also affected by the timing of releases from Bridgeport Reservoir. 3. The quarterly SWAMP data are insufficient to establish baseline and trend conditions as required under Section 4.10 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 there is insufficient information to show that 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):	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 6540, Sedimentation/Siltation	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

4609

Pollutant:

Sedimentation/Siltation

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 6540, Sedimentation/Siltation	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5051

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 under the Region 6 SWAMP program, at quarterly intervals between 2001 and 2005, and did load calculations based on concurrent flows. Suspended sediment concentrations in 16 samples ranged from 5 to 28 mg/L. Calculated sediment loads in 8 samples ranged from 0.37 to 23 tons/day. Sampling frequency is insufficient to evaluate compliance with the objective.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's narrative objective 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Sixteen quarterly samples were collected between 2001 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7624	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Aluminum
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 exceed the applicable water quality objective and criterion. 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 four samples exceeded the water quality objective or freshwater aquatic life criterion, 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 7624, Aluminum	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5065

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 aluminum under the Region 6 SWAMP program in 2001 and 2002. Total recoverable aluminum concentrations in four samples ranged from 59 to 110 ug/L. The state MCLs were not exceeded.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 primary MCL for aluminum is 1000 ug/L and the secondary MCL is 200 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7624, Aluminum	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5746

Pollutant:

Aluminum

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 aluminum under the Region 6 SWAMP program in 2001 and 2002. Concentrations of dissolved aluminum in four samples ranged from 2 to 18 ug/L. The aquatic life criteria were not exceeded.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The U.S. Environmental Protection Agency acute freshwater aquatic life criterion for aluminum is 750 ug/L, and the chronic criterion is 87 ug/L. Aquatic life criteria are expressed as dissolved metals.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7683	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 exceed the aquatic life criteria or the 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 seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the water quality objective or criteria 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 7683, Antimony	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7716

Pollutant:

Antimony

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 antimony under the Region 6 SWAMP program in 2001 and 2002. Four dissolved antimony samples all had concentrations below the detection limit. Per listing policy Section 6.1.5.5, the criteria are presumed to be attained.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The USEPA Lowest Observed Effect Levels (LOEL) criteria for protection of aquatic life include an acute antimony value of 9000 ug/L, a chronic value of 1600 ug/L and a limit for toxicity to algae of 610 ug/L

Objective/Criterion Reference:

Compilation of Water Quality Goals

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7683, Antimony	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5122

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 antimony under the Region 6 SWAMP program in 2001 and 2002. Four total antimony samples all had concentrations below the detection limit. Per listing policy Section 6.1.5.5, the MCL and CTR standard are presumed to be attained.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 California primary MCL for antimony is 6 ug/L. The California Toxics Rule water and fish consumption standard is 14 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7626	Region 6
East Walker River, below Bridgeport Reservoir

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. One 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 are inadequate to document variations in arsenic concentrations over time, particularly at a station where flows depend on upstream reservoir releases. 3. One of four 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 7626, Arsenic	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5031

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 under the Region 6 SWAMP program. Concentrations of total arsenic in four samples ranged from 3 to 18 ug/L. One sample exceeded the California MCL.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7626, Arsenic	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5030

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 under the Region 6 SWAMP program. Dissolved arsenic concentrations in four samples ranged from 2 to 18 ug/L. The CTR standards were not exceeded.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7640	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 exceed the applicable water quality objective and criteria. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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 8 samples exceeded the applicable water quality objective and criteria, 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 7640, Beryllium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5068

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 beryllium under the Region 6 SWAMP program in 2001 and 2002. Four total recoverable beryllium samples had reported concentrations less than the detection limit. Per listing policy Section 6.1.5.5, the MCL is presumed to be attained.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 beryllium is 4 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7640, Beryllium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5763

Pollutant:

Beryllium

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 beryllium quarterly in the East Walker River under the Region 6 SWAMP program in 2001 and 2002. Four dissolved beryllium samples had reported concentrations below the detection level. Per listing policy Section 6.1.5.5, the objective is presumed to be attained.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The U.S. Environmental Protection Agency's (USEPA's) freshwater aquatic life criteria for beryllium are as follows: acute (1 hour average) criterion = 130 ug/L; chronic (4 day average) criterion = 5.3 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8696	Region 6
East Walker River, below Bridgeport Reservoir

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. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeded the criterion. 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 four samples exceeded the California Notification Level criterion. 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 8696, Boron	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7686

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 under the Region 6 SWAMP program, at quarterly intervals between 2002 and 2005. Boron concentrations in 9 samples ranged from 39 to 178 ug/L. The criterion was not exceeded.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Drinking Water Notification and Response Levels: An Overview

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Nine quarterly samples were collected between 2002 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8684	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the California Toxics Rule standards or 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 seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded 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 8684, Cadmium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5070

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 cadmium under the Region 6 SWAMP program in 2001 ad 2002. Four total cadmium samples had reported concentrations less than the detection limit. Per listing policy Section 6.1.5.5, the MCL is presumed to be attained.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 Constituent" objective. The MCL for cadmium is 5 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8684, Cadmium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7689

Pollutant:

Cadmium

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:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) aquatic life standards for cadmium are hardness-based. At the hardness levels measured for this station, the acute toxicity standard ranges from 2.29 to 2.75 ug/L and the chronic toxicity standard ranges from 1.45 to 1.65 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8685	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Calcium
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 of evidence are available in the administrative record to assess this pollutant. There are no California or federal standards or water quality criteria for calcium. 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 satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. There are no applicable standards or criteria and the data cannot be assessed pursuant to 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 there are no applicable water quality standards or criteria.

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 8685, Calcium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7719

Pollutant:

Calcium

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 East Walker River under the Region 6 SWAMP program in 2001 and 2002. Concentrations of dissolved calcium in four samples ranged from 17 to 20 mg/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for calcium for the protection of freshwater aquatic life.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8685, Calcium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7720

Pollutant:

Calcium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 the East Walker River under the Region 6 SWAMP program in 2001 and 2002. Concentrations of total calcium in four samples ranged from 16.9 to 18.6 mg/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for calcium 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7627	Region 6
East Walker River, below Bridgeport Reservoir

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. One line of evidence is available in the administrative record to assess this pollutant. None of the samples or calculated exceed the 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 seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of the 16 samples exceeded the applicable 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 7627, Chloride	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5040

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:

The U.S. Geological Survey sampled chloride under the Region 6 SWAMP program, at quarterly intervals between 2002 and 2005. Chloride concentrations in 16 samples ranged from 0.58 to 5.35 mg/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Sixteen quarterly samples (2 to 4 samples per year) were collected between 2001 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8686	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Chromium (total)
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 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 constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the Califoria Toxics Rule standards or the 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 8686, Chromium (total)	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7695

Pollutant:

Chromium (total)

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 the East Walker River under the Region 6 SWAMP program. Concentrations of dissolved chromium in four quarterly samples were all below the detection level. Under Listing Policy section 6.1.5.5 the standards are presumed to be attained.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) standards for dissolved Chromium VI to protect freshwater aquatic life are11 ug/L ( 4-day average) and,16 ug/L (1 hour average). The CTR standard for Chromium III is hardness dependent. At the hardness levels reported for this station, acute (1 hour average) limits for Chromium III range from 349.71 to 398.82 ug/L. The chronic (4 day average) limits range from 113.41 to 129.37 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8686, Chromium (total)	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5748

Pollutant:

Chromium (total)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 the East Walker River under the Region 6 SWAMP program. Concentrations of total chromium in four quarterly samples were all below the detection level. Under Listing Policy section 6.1.5.5 the MCL is presumed to be attained.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 chromium is 50 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8687	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Cobalt
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. There are no California or federal water quality standards or criteria for cobalt. 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. There are no applicable standards or criteria. Therefore the data cannot be assessed using Table 3.1 of the Listing Policy.After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board. 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 there are no applicable state or federal standards or criteria.

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 8687, Cobalt	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7700

Pollutant:

Cobalt

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 the East Walker River under the Region 6 SWAMP program in 2001 and 2002. Four samples had concentrations of total recoverable cobalt below the detection level.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for cobalt 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8687, Cobalt	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7698

Pollutant:

Cobalt

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 East Walker River under the Region 6 SWAMP program in 2001 and 2002. Concentrations of dissolved cobalt in four samples ranged from 0.07 to 0.168 ug/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for cobalt for the protection of freshwater aquatic life.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7628	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 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 constituent concentrations in streams of the Lahontan Region. 3. None of 8 samples exceeded the applicable water quality objective and California Toxics Rule standard, 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 the applicable water quality objective and California Toxics Rule standard 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 7628, Copper	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5069

Pollutant:

Copper

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 copper under the Region 6 SWAMP program in 2001 and 2002. Dissolved copper concentrations in 4 samples ranged from 0.7 to 1.6 ug/L. The CTR standards were not violated.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) freshwater aquatic life standards for copper are hardness-dependent, At the hardness levels reported for this station, the acute (1 hour average) standard ranges from 8.00 to 9.31 ug/L The chronic (4 day average) standard ranges from 5.60 to 6.42 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7628, Copper	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5076

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 copper under the Region 6 SWAMP program in 2001 and 2002. Total recoverable copper concentrations in 4 samples ranged from 1.0. to 1.4 ug/L. The MCLs were not exceeded.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) are applicable under the Lahontan Basin Plan's Chemical Constituents objective. The primary MCL for copper is 1300 ug/L and the secondary MCL is 1000 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	16123	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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. No biological data are available to determine whether either of the samples exceeds the water quality objective for biostimulatory substances. 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. 3. No biological data are available to assess compliance with the objective and the chemical data cannot be assessed using 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 16123, Dissolved Kjeldahl Nitrogen	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7748

Pollutant:

Dissolved Kjeldahl Nitrogen

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 collected two samples under the Region 6 SWAMP program in August and November 2003. Concentrations of dissolved Kjeldahl nitrogen were 0.9 and 0.38 mg/L. No associated data on algae or macrophytes were available for assessment of compliance with the objective for biostimulatory substances.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no site-specific objectives for dissolved Kjeldahl nitrogen. The Lahontan Basin Plan's narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Two samples were collected in August and November 2003.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8688	Region 6
East Walker River, below Bridgeport Reservoir

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 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 expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. None of 6 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 8688, Dissolved oxygen saturation	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5815

Pollutant:

Dissolved oxygen saturation

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Aquatic Life Use:

Fish Spawning

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 percent saturation of dissolved oxygen quarterly between November 2003 and August 2005 under the Region 6 SWAMP program. Percent saturation in 6 measurements ranged from 88 to 119 percent. The objective was not violated.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's narrative objective states that percent saturation shall not be depressed by more than 10 percent and minimum dissolved oxygen concentration shall not be less than 80 percent saturation.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, the East Walker River near state line, was sampled.

Temporal Representation:

Six quarterly measurements were taken between November 2003 and August 2006.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7679	Region 6
East Walker River, below Bridgeport Reservoir

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. 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 fecal coliform counts in streams of the Lahontan Region. The water quality objective calls for five samples to be collected within a 30-day period. 3. None of six 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 7679, Fecal Coliform	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5694

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:

The U.S. Geological survey sampled fecal coliform bacteria under the Region 6 SWAMP between 2003 and 2005. Bacteria counts in five of six samples were estimated values, and the count in one sample was below the detection level. The objective was not violated.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's water quality 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Six quarterly samples were collected at approximately quarterly intervals between November 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 7679, Fecal Coliform	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5695

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 sampled fecal coliform bacteria under the Region 6 SWAMP program between 2003 and 2005. Bacteria counts in five of six samples were estimated values, and the count in one sample was below the detection level. The objective was not violated.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Six samples were collected approximately quarterly between November 2003 and August 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8817	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Hardness as CaCO3
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	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. There are no applicable state or federal standards or criteria. The hardness data assessed fall within the category generally considered "soft". Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy in that only four quarterly samples were available. The minimum sample number requirements of Listing Policy Table 3.2 are not met. 3. There are no applicable standards or criteria. 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 there are no applicable standards or criteria and the minimum sample number requirements 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 8817, Hardness as CaCO3	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7812

Pollutant:

Hardness as CaCO3

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 the East Walker River under the Region 6 SWAMP program in 2001 and 2002. Hardness values in four quarterly samples were 57.69, 67.73, 62.80, and 61.84 mg equivalent CaC03/L. These values are within the range characterizing "soft" water.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for hardness. Hardness is monitored for purposes such as determination of the applicable criteria and standards for metals whose toxicity is hardness-dependent. The U.S. Environmental Protection Agency's 1986 "Gold Book" includes generally accepted categories of hardness. Calcium and magnesium are the major ions contributing to hardness, and hardness is generally expressed as calcium carbonate. Water with a hardness equivalent to 0-75 mg equivalent CaC03/L is considered "soft."

Objective/Criterion Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8817, Hardness as CaCO3	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7815

Pollutant:

Hardness as CaCO3

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 West Walker River and East Walker River Hydrologic Units

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7680	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 exceed the freshwater aquatic life criterion or the 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 seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the applicable water water quality objective or criterion 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 7680, Iron	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7710

Pollutant:

Iron

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 iron under the Region 6 SWAMP program in 2001 and 2002. Dissolved iron concentrations in two of four samples were estimated values. Dissolved iron concentrations in the remaining samples were samples 29 and 71 ug/L. The criterion was not violated.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The U.S. Environmental Protection Agency's national freshwater aquatic life criterion for iron is a 4-day average of 1000 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7680, Iron	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5081

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 iron under the Region 6 SWAMP program in 2001 and 2002. Total recoverable iron concentrations in 4 samples ranged from 210 to 260 ug/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 secondary MCL for iron is 300 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7629	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 exceeded the applicable water quality objective and California Toxics Rule standard. 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 eight samples exceeded the applicable water quality objective and California Toxics Rule standard 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 7629, Lead	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5121

Pollutant:

Lead

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 lead under the Region 6 SWAMP program in 2001 and 2002. Dissolved lead concentrations in four samples included two values below the detection level, one estimated value, and one 0.16 ug/L value. The CTR standards were not exceeded.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxic Rule (CTR) standards for lead are dependent on hardness. At the reported hardness levels for this station, the acute (1 hour average) standard ranged from 32.06 to 39.33 ug/L. The chronic (4 day average) standard ranged from 1.25 to 1.53 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7629, Lead	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5120

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 lead under the Region 6 SWAMP program in 2001 and 2002. Concentrations of total recoverable lead in four quarterly samples were below the detection limit. Per listing policy Section 6.1.5.5, the MCL is presumed to be attained.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 lead is 15 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8689	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Magnesium
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. There are no applicable standards, objectives or criteria for magnesium. 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. 3. There are no applicable standards, objectives or criteria for evaluation of the four samples for dissolved magnesium or four samples for total magnesium 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 there are no applicable standards, water quality objectives or criteria.

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 8689, Magnesium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7722

Pollutant:

Magnesium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 the East Walker River under the Region 6 SWAMP program in 2001 and 2002. Concentrations of total magnesium in four samples ranged from 3.64 to 4.09 mg/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for magnesium 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8689, Magnesium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7721

Pollutant:

Magnesium

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 East Walker River under the Region 6 SWAMP program in 2001 and 2002. Concentrations of dissolved magnesium in four samples ranged from 3.7 to 4.32 mg/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for magnesium for the protection of freshwater aquatic life.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7682	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 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 constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the applicable water quality objective and criteria, 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 7682, Mercury	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5082

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 mercury under the Region 6 SWAMP program in 2001 and 2002. Mercury concentrations in four samples ranged from less than 0.01 ug/L to 0.01 ug/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 MCL tor inorganic mercury is 2 ug/L.

The California Toxics Rule water and fish consumption standard for mercury is 0.050 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7682, Mercury	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5764

Pollutant:

Mercury

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 U.S. Geological Survey sampled mercury quarterly in the East Walker River under the Region 6 SWAMP program in 2001 and 2002. Three of four total mercury samples were below the detection level, and one was 0.01 ug/L The criteria were not violated.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The U.S. Environmental Protection Agency (USEPA) freshwater aquatic life criteria (expressed as total mercury) are a 4- day average of 0.77 ug/L and a 1-hour maximum of 1.4 ug/L

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

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

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8690	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Molybdenum
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. There are no applicable water quality standards or criteria. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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. There are no applicable water quality standards or criteria and the data cannot be assessed using 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 there are no applicable water quality standards or criteria.

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 8690, Molybdenum	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7709

Pollutant:

Molybdenum

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 East Walker River under the Region 6 SWAMP program in 2001 and 2002. Concentrations of dissolved molybdenum in four samples ranged from 4.3 to 4.8 ug/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for cobalt for the protection of freshwater aquatic life.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8690, Molybdenum	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7707

Pollutant:

Molybdenum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 the East Walker River under the Region 6 SWAMP program in 2001 and 2002. Total recoverable molybdenum concentrations in four samples ranged from 4.4 to 4.9 ug/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no applicable state or federal standards or criteria for molybdenum for protection of the Municipal and Domestic Supply use.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7681	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 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 constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the applicable objectives 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 7681, Nickel	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5119

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 nickel under the Region 6 SWAMP program in 2001 and 2002. Dissolved nickel concentrations in 4 samples ranged from less than 0.06 ug/L to 0.28 ug/L. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 nickel is 100 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7681, Nickel	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5089

Pollutant:

Nickel

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:

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) freshwater aquatic life standards for nickel are dependent on hardness. At the hardness levels reported for this station, the acute (1-hour average) standard ranges from 234.01 to 336.75 ug/L. The chronic (4-day average) standard ranges from 32.69 to 37.44 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	16122	Region 6
East Walker River, below Bridgeport Reservoir

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 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 16 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 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 16122, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5034

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 U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of nitrite plus nitrate in 16 quarterly samples ranged from below detection level to 0.42 mg/L. One sample was an estimated value. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 nitrite plus nitrate is 10 mg/L expressed "as nitrogen."

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Sixteen quarterly samples were collected between 2001 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	16124	Region 6
East Walker River, below Bridgeport Reservoir

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 lines of evidence are available in the administrative record to assess this pollutant. The single sample does not 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. 3. The single sample does not exceed 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 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 16124, Nitrite as Nitrite NO2	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7747

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 U.S. Geological Survey collected one NO2-N sample under the Region 6 SWAMP program on 6/28/2002. The nitrite concentration was 0.011 mg/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

One sample was collected on 6/28/2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8691	Region 6
East Walker River, below Bridgeport Reservoir

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. Four of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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 dissolved oxygen concentrations in streams of the Lahontan Region. 3. Four of 15 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 8691, Oxygen, Dissolved	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5731

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Aquatic Life Use:

Fish Spawning

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 quarterly between 2001 and 2005 under the Region 6 SWAMP program. Dissolved oxygen concentrations in 15 samples ranged from 7.1 to 12 mg/L. Four of 15 samples were below the 8 mg/L minimum concentration.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

For waters designated for the COLD and SPWN beneficial uses the 1- day minimum objective is 8 mg/L (Lahontan 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, the East Walker River near state line, was sampled.

Temporal Representation:

Fifteen quarterly samples were collected between August 2002 and August 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	16415	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Phosphate
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. No biological data are available to evaluate whether any 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 full range of seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. No biological data are available for assessment of compliance with the water quality objective and the data cannot be assessed using 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 16415, Phosphate	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7792

Pollutant:

Phosphate

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 U.S. Geological survey sampled the East Walker River under the Region 6 SWAMP program in 2002 and 2003. Concentrations of PO4-P in 3 samples ranged from 0.03 to 1.61 mg/L. No biological data are available for assessment of compliance with the objective for biostimulatory substances.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no site specific numerical objectives for phosphate for this segment. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Three quarterly samples were collected in 2002 and 2003.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8692	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 line of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the California Toxics Rule standards or the 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 seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the Califonia Toxics Rule standards or the 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 8692, Selenium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5123

Pollutant:

Selenium

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 selenium under the Region 6 SWAMP program in 2001 and 2002. Dissolved selenium concentrations in 3 of 4 samples were below the detection level. The concentration in the remaining sample was an estimated value. The CTR standards were not exceeded.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) standards for protection of freshwater aquatic life are as follows: 4 day average = 5.0 ug/L; 1-hour average = 20 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8692, Selenium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7713

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 selenium under the Region 6 SWAMP program in 2001 and 2002. Concentrations of total selenium in 3 of 4 samples were estimated values, and the fourth sample was below the detection level. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 selenium is 50 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7625	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 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 constituent concentrations in streams of the Lahontan Region. 3. None of eight samples exceeded the applicable water quality objectives 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 7625, Silver	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5061

Pollutant:

Silver

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 silver under the Region 6 SWAMP program. Four dissolved silver samples had concentrations less than 1.0 ug/L, the presumed detection limit. Per listing policy Section 6.1.5.5, the objective and CTR standards are presumed to be attained.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule standard for silver (for protection of freshwater aquatic life) is dependent on hardness. At the hardness values reported for this station, the instantaneous maximum standard ranges from 1.34 to 1.77 ug/L

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7625, Silver	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5064

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 silver under the Region 6 SWAMP program. Four total silver samples had concentrations less than 0.05 ug/L, the detection limit. Per listing policy Section 6.1.5.5, the objective is presumed to be attained.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 MCL for silver is 100 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7639	Region 6
East Walker River, below Bridgeport Reservoir

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 Lahontan Region. 3. None of 14 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 7639, Specific Conductance	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5050

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 under the Region 6 SWAMP program, at quarterly intervals between 2001 and 2005. Fourteen field measurements of specific conductance ranged from 144 to 271 uS/cm. An additional 6 laboratory measurements were taken for samples collected on the same dates as field measurements. Laboratory specific conductance ranged from 151 to 202 uS/cm. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Fourteen quarterly field measurements and 6 laboratory measurements of specific conductance were taken between 2001 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7678	Region 6
East Walker River, below Bridgeport Reservoir

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. One 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 constituent 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 7678, Sulfates	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5052

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 sulfate under the Region 6 SWAMP program between 2003 and 2005. Sulfate concentrations in 7 samples ranged from 5.1 to 23 mg/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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)

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Seven samples were collected approximately quarterly between November 2003 and August 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7677	Region 6
East Walker River, below Bridgeport Reservoir

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 7677, Temperature, water	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5055

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 measured water temperature at quarterly intervals under the Region 6 SWAMP program between 2001 and 2005. Sixteen water temperature measurements ranged from 0 to 22.5 degrees Celsius. Sampling frequency was not sufficient to determine the natural seasonal and annual temperature range or the extent to which changes occur due to human activities such as reservoir management.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Sixteen quarterly samples were collected between 2001 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7685	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 exceed the water quality criteria or the 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 seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the applicable objective or criteria 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 7685, Thallium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5124

Pollutant:

Thallium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 thallium. under the Region 6 SWAMP program. Concentrations of total thallium in four samples were all below the detection level. Per listing policy Section 6.1.5.5, the objective is presumed to be attained.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 MCL for thallium is 2 ug/L.

The California Toxics Rule water and fish consumption standard (for waters designated MUN) is 1.7 ug/L

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7685, Thallium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7712

Pollutant:

Thallium

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 thallium under the Region 6 SWAMP program. Dissolved thallium concentrations in four samples were all below the detection limit. Per listing policy Section 6.1.5.5, the objective is presumed to be attained.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The U.S. Environmental Protection Agency's Lowest Observed Effect Levels (LOEL) criteria include an acute toxicity value of 1400 ug/L,and a chronic toxicity value of 40 ug/L. The criteria also include an "Other" limit of 20 ug/L based on 2600 hour exposure of one fish species.

Objective/Criterion Reference:

Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7642	Region 6
East Walker River, below Bridgeport Reservoir

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 Maximum Contaminant Level. None of the annual average datapoints exceeds the site-specific 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 15 samples exceeded the California Maximum Contaminant Level. None of five annual average 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 7642, Total Dissolved Solids	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5053

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 TDS under the Region 6 SWAMP program at quarterly intervals between 2001 and 2005. Two different laboratory methods were used. TDS concentrations in 15 individual samples analyzed as "residue" ranged from 90 to 186 mg/L. Of two additional samples analyzed as "nonfilterable" , one was below detection level and the other was 11 mg/L. (The "residue" TDS concentration on the same date was 121 mg/L.) There were no violations of the annual average objective in five years of sampling.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site-specific objective for Total Dissolved Solids (TDS) includes an annual average of 45 mg/L and a 90th percentile value of 160 mg/L (Lahontan Basin Plan Table 3-15).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Fifteen TDS samples analyzed as "residue" were collected between 2001 and 2005. Two additional samples collected in 2003 and 2004 were analyzed as "nonfilterable."

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 7642, Total Dissolved Solids	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5054

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 under the Region 6 SWAMP program, at quarterly intervals between 2001 and 2005. TDS concentrations in 15 samples analyzed as "residue" ranged from 90 to 186 mg/L. One of two additional samples analyzed as "nonfilterable" had a TDS concentration below detection level; the other sample had a concentration of 11 mg/L. The MCL was not violated.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for Total Dissolved Solids (TDS) 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Fifteen TDS samples analyzed as "residue" were collected quarterly between 2001 and 2005. Two additional samples analyzed as "nonfilterable" were collected in 2003 and 2004..

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8694	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Vanadium
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. There are no applicable standards or criteria for protection of aquatic life. None of the samples exceed the California Notification Level criterion. 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 four samples exceeded the criterion 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 the applicable water quality criterion is 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 8694, Vanadium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7715

Pollutant:

Vanadium

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 vanadium under the Region 6 SWAMP program. Concentrations of dissolved vanadium in four samples were all below the detection level. Per listing policy Section 6.1.5.5, the criterion is presumed to be attained.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for vanadium for the projection of freshwater aquatic life.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 8694, Vanadium	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7714

Pollutant:

Vanadium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 vanadium under the Region 6 SWAMP program. Concentrations of total vanadium in four samples were all below the detection level. Per listing policy Section 6.1.5.5, the criterion is presumed to be attained.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Notification Level criterion for vanadium in drinking water is 50 ug/L.

Objective/Criterion Reference:

Drinking Water Notification and Response Levels: An Overview

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7650	Region 6
East Walker River, below Bridgeport Reservoir

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

Regional Board Conclusion:	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 exceed the applicable water quality objective and California Toxics Rule standard. 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 8 samples exceeded the applicable objective and California Toxics Rule standard, 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 7650, Zinc	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5126

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 zinc under the Region 6 SWAMP program in 2001 and 2002. Four total zinc samples had concentrations ranging from below the detection level to 2 ug/L. The MCL was not violated. .

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 MCL for zinc is 5000 ug/L.

The California Toxics Rule water and fish consumption standard (for waters designated MUN) is 1.7 ug/L

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7650, Zinc	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5125

Pollutant:

Zinc

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 zinc quarterly under the Region 6 SWAMP program in 2001 and 2002. Dissolved zinc concentrations in three of four samples were below the detection level and the fourth sample was 2 ug/L. The CTR standards were not violated. .

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) freshwater aquatic life standards for zinc are dependent on hardness. At the hardness levels reported for this station, the acute (1-hour average) standard ranges from 73.53 to 84.23 ug/L and the chronic (4-day average) standard ranges from 74.13 to 84.92ug/L.)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8695	Region 6
East Walker River, below Bridgeport Reservoir

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 is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. (A pH range of 6.5 to 8.5 units applies to "all other waters.") 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 the 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 8695, pH	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5043

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 sampled pH under the Region 6 SWAMP program, at quarterly intervals between 2002 and 2005. Fifteen field measurements had pH values ranging from 7.8 to 9.7 units. Three measurements exceeded 8.5 units. Five laboratory pH measurements ranged from 7.4 to 8.5 units. However, the 6.5 to 8.5 unit limit does not apply to waters designated for the COLD use.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's narrative objectives for pH states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units.

The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Fifteen field measurements of pH were taken quarterly between 2001 and 2005. Five laboratory measurements were taken in samples collected on the same dates as the corresponding field measurements.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	7684	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Manganese
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:	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. Four of the samples exceed the California Maximum Contaminant Level. Listing is not being recommended because the data are not temporally representative. 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 concentrations in streams of the Lahontan Region. This segment of the East Walker River is also affected by the timing of releases from Bridgeport Reservoir. 3. Four of four samples exceeded the California Maximum Contaminant Level 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. State Board Review and Conclusion: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for manganese based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. The State Water Board recommendation is based on the following: Lahontan Regional Board staff had decided not to list this water body because staff thought it had insufficient information to make a decision to list. However, State Board staff finds there are 4 samples to make a decision and this meets the sample size requirements of Table 3.1 of the Listing Policy. On August 4, 2010 the State Water Board approved the staff recommendation to place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is: 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 satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Four of four samples exceeded the California Maximum Contaminant Level 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 not be placed on the section 303(d) list because, although the standard is being exceeded, the data are not temporally representative.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the following changes to the decision: The water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

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 7684, Manganese	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5085

Pollutant:

Manganese

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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 manganese under the Region 6 SWAMP program in 2001 and 2002. Total manganese concentrations in 4 samples ranged from 82 to 119 ug/L. All four samples exceeded the MCL.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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 secondary MCL for manganese is 50 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

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 7684, Manganese	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7711

Pollutant:

Manganese

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 U.S. Geological Survey sampled manganese under the Region 6 SWAMP program in 2001 and 2002. Concentrations of dissolved manganese in four samples ranged from 11.6 to 36.5 ug/L.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal standards or criteria for manganese 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four quarterly samples were collected in 2001 and 2002.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	8693	Region 6
East Walker River, below Bridgeport Reservoir

Pollutant:	Turbidity
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:	Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under sections 3.2 and 3.10 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines are available in the the administrative record to assess this pollutant. There are no applicable standards or criteria for turbidity expressed as NTRU. The Lahontan Basin Plan's narrative turbidity objective, expressed as NTU and used to assess the aquatic life use, is antidegradation based. Sample numbers are insufficient to establish baseline-trend conditions for assessment of compliance with this objective under Listing Policy section 3.10. Nine of the samples expressed as NTU exceed the California Maximum Contaminant Level(MCL). However, listing is not recommended because the data are not temporally representative. 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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Nine of 12 samples exceeded the California Maximum Contaminant Level and this exceeds 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. State Board Review and Conclusion: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for turbidity based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. The State Water Board recommendation is based on the following: Lahontan Regional Board staff had decided not to list this water body because staff thought it had insufficient information to make a decision to list. However, State Board staff finds there are 12 samples to make a decision and this meets the sample size requirements of Table 3.2 of the Listing Policy. On August 4, 2010 the State Water Board approved the staff recommendation to place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is: 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 satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Nine of 12 samples exceeded the California Maximum Contaminant Level and this exceeds 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 although one of the applicable water quality standards is being exceeded, the data are not temporally representative.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the following changes to the decision: The water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

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 8693, Turbidity	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5056

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:

The U.S. Geological Survey measured turbidity under the Region 6 SWAMP program at quarterly intervals between 2001 and 2004. Twelve turbidity samples reported as NTU ranged from below the detection level to 12 NTU.

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The applicable objective in the Lahontan Basin Plan states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Twelve samples reported as NTU were collected quarterly from 2001 to 2004.

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 8693, Turbidity	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

5057

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 measured turbidity under the Region 6 SWAMP program at quarterly intervals between 2001 and 2004. Turbidity in 12 samples ranged from below the detection level to 12 NTU. The MCL was exceeded in 9 of the 12 samples.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Twelve samples reported as NTU were collected quarterly between 2001 to 2004.

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 8693, Turbidity	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7718

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 measured turbidity under the Region 6 SWAMP program at quarterly intervals between 2004 and 2005. Turbidity in 4 samples ranged from 2 to 4.2 NTRU. Since the MCL is expressed as NTU these samples cannot be used to assess compliance.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four samples reported as NTRU were collected quarterly between 2004 and 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 8693, Turbidity	Region 6
East Walker River, below Bridgeport Reservoir

LOE ID:

7717

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:

The U.S. Geological Survey measured turbidity under the Region 6 SWAMP program at quarterly intervals between 2004 and 2005. Turbidity in 4 samples ranged from 2 to 4.2 NTRU.

Data Reference:

2007. SWAMP Data for the West Walker River and East Walker 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, East Walker River at the California-Nevada State Line, was sampled.

Temporal Representation:

Four samples reported as NTU were collected quarterly in 2004 and 2005.

Environmental Conditions:

QAPP Information:

Data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):