Draft 2008 California 303(d)/305(b) Integrated Report

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Robinson Creek (Barney Lake to Twin Lakes)
Water Body ID: CAR6304003220021009155537
Water Body Type: River & Stream
 
DECISION ID
9989
 
Pollutant: Acid Neutralizing Capacity
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
 
Weight of Evidence: 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. Acid Neutralizing Capacity (ANC) is equivalent to alkalinity, and the USEPA "Gold Book" criterion for alkalinity states that it should be greater than 20 mg/L CaCO3 unless natural alkalinity is lower. Only one ANC sample is available for Robinson Creek, at 7.9 mg/L CaCO3.. There is insufficient information to determine the natural range of ANC.

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. It is not possible to determine whether the single sample exceeds the criterion. The minimum sample number requirements of Table 3.2 of the Listing Policy are not met.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the minimum sample number requirements of Listing Policy Table 3.2 are not met..
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9989
 
LOE ID: 21347
 
Pollutant: Acid Neutralizing Capacity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured acid neutralizing capacity for this station in one sample collected on March 11, 2003. The ANC was 7.9 mg/L CaCO3.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: There are no California or federal standards or criteria for acid neutralizing capacity (ANC) per se. However, ANC is equivalent to alkalinity, and the U.S. Environmental Protection Agency "Gold Book" recommends alkalinity greater than 20 mg/L CaCO3 unless natural alkalinity is lower.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: One sample was collected on March 11. 2003..
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9991
 
Pollutant: Ammonia
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: 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 expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 4 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.
 
RWQCB Board Decision / Staff Recommendation: After review of 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9991
 
LOE ID: 21352
 
Pollutant: Ammonia
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station in 2002 and 2003 under the Region 6 SWAMP program. Concentrations of ammonia in 4 quarterly samples were all below the detection level.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: At the reported pH and temperature levels, the applicable objectives from Lahontan Basin Plan Table 3-1 are as follows. The 1-hour average limits for unionized ammonia range from 0.0129 to 0.091 mg/L NH3. The 1-hour average limits for total ammonia range from 17.4 to 33 mg/L NH3.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly samples were taken in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10003
 
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
 
Weight of Evidence: 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. There are no biological data available for assessment of compliance with 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. 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 biological data available for assessment whether the chemical samples comply with the objective. 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.
 
RWQCB Board Decision / Staff Recommendation: After review of 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 biological data available for assessment of compliance with the applicable water quality objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10003
 
LOE ID: 21348
 
Pollutant: Dissolved Kjeldahl Nitrogen
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Robinson Creek under the Region 6 SWAMP program in 2002 and 2003. Two of 4 quarterly samples for dissolved Kjeldahl nitrogen were below the detection level. The concentration in one sample was an estimate. The fourth sample had a concentration of 0.11 mg/L.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's 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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly samples were taken between June 2002 and June 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7602
 
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
 
Weight of Evidence: 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. The single sample did not exceed the water quality objective. The minimum sample number requirements of listing policy Table 3-2 were not met.

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

Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the minimum sample number requirements of the Listing Policy were not met.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7602
 
LOE ID: 5698
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Robinson Creek below Barney Lake four times in 2002 and 2003 under the Region 6 SWAMP program. Only one fecal coliform bacteria sample was collected, and its value was one colony per 100 mL. Sample numbers were insufficient to assess compliance with the standard.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide Water Quality objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected as 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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: One sample for fecal coliform bacteria was collected in June 2002.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 5699
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Robinson Creek below Barney Lake four times in 2002 and 2003 under the Region 6 SWAMP program. Only one fecal coliform bacteria sample was collected, and its value was one colony per 100 mL. Sample numbers were insufficient to assess compliance with the standard.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide Water Quality objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected as 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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: One sample for fecal coliform bacteria was collected in June 2002.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9998
 
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
 
Weight of Evidence: 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 expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 4 samples exceeded the California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9998
 
LOE ID: 21350
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station in 2002 and 2003 under the Region 6 SWAMP program. Concentrations of nitrite plus nitrate in four quarterly samples were all 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.
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite plus nitrate is 10 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly samples were taken in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7724
 
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
 
Weight of Evidence: 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. Data quality meets the requirements of Listing Policy section 6.1.4. Data quantity does not meet the requirements of Listing Policy section 6.1.5. The single sample did not exceed the water quality objective. However, the minimum sample number requirements of Listing Policy Table 3-2 were not met.

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

Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the minimum sample number requirements of the Listing Policy were not met.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7724
 
LOE ID: 5009
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 1
Number of Exceedances: 0
 
Data and Information Type: 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. The dissolved oxygen concentration in one sample taken on June 5, 2002 was 9.1 mg/L.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The objective for waters designated COLD and SPWN is a 1 day minimum of 8 mg/L (Lahontan Basin Plan Table 3-6)
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: One sample was taken on June 5, 2002.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7771
 
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
 
Weight of Evidence: 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 for assessment of compliance with the 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. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. All four samples were below the detection level. No biological data are available for assessment of compliance with the objective.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of 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 no biological data are available for assessment of compliance with the objective..
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7771
 
LOE ID: 6078
 
Pollutant: Phosphate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Robinson Creek under the Region 6 SWAMP program in 2002 and 2003. Four quarterly phosphate samples were all below the detection level. Per Listing Policy Section 6.1.5.5 the standard is presumed to be attained.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not contain a site-specific objective for phosphate in Robinson Creek. (It does include an objective for total phosphorus, which is assessed in a separate line of evidence.) The Basin Plan's 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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly samples were taken between June 2002 and June 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7772
 
Pollutant: Phosphorus
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
 
Weight of Evidence: 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. Neither of two annual average datapoints exceeds the water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. Neither of two annual average datapoints exceeded the objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7772
 
LOE ID: 5016
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Robinson Creek under the Region 6 SWAMP program in 2002 and 2003. One of four quarterly samples for total phosphorus was an estimated value. The other three ranged from 0.004 to 0.01 mg/L. Annual averages based on these values did not exceed the objective.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The water quality objective for total phosphorus is an annual average of 0.2 mg/L and a 90th percentile value of 0.02 mg/L (Lahontan Basin Plan Table 3-15).
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly samples were taken between June 2002 and June 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7788
 
Pollutant: Sediment
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: The Lahontan Basin Plan's narrative water quality objective is an antidegradation based objective that provides that there shall be no increases in suspended sediment concentrations or loads. This pollutant is being considered for placement on the section 303(d) list under section 3.10 of the Listing Policy, which deals with trends in water quality.

One line of evidence, based on quarterly sampling, is available in the administrative record to assess this pollutant. It includes only 4 suspended sediment samples.

Suspended sediment concentrations and loads are dependent on flows and can change rapidly over a short time during storm or snowmelt runoff events. Quarterly samples are insufficient to capture these short term events and therefore are insufficient to define natural background suspended sediment concentrations and loads, or to detect trends. Listing Policy Section 3.10 requires that natural background conditions be established.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy Section 3.10.
3. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of 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 requirements of Listing Policy section 3.10 are not met.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7788
 
LOE ID: 5028
 
Pollutant: Sediment
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey collected suspended sediment samples at quarterly intervals in 2002 and 2003. Concentrations in four samples ranged from 0 to 2 mg/L.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly samples were taken in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7603
 
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
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

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

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

This conclusion is based on the staff findings that:
1. The data used 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 five samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. However, the minimum sample number requirements of Table 3.2 are not met.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the minimum sample number requirements of the Listing Policy are not met.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7603
 
LOE ID: 5021
 
Pollutant: Specific Conductance
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured specific conductance in 2002 and 2003 under the Region 6 SWAMP program. Four quarterly measurements ranged from 8 to 40 uS/cm, and an additional measurement, reported as "field" specific conductance was 43 uS/cm. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly measurements of specific conductance and an additional measurement by a different method were taken in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7759
 
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
 
Weight of Evidence: 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.
 
RWQCB Board Decision / Staff Recommendation: After review of 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 Table 3-2 and Sections 3.10 and 6.1.5.9.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7759
 
LOE ID: 5022
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured temperature at quarterly intervals in 2002 and 2003 under the Region 6 SWAMP program. Four temperature measurements ranged from 2 to 13.5 degrees Celsius.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four temperature measurements were taken at quarterly intervals in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10010
 
Pollutant: Total Kjeldahl Nitrogen (TKN)
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
 
Weight of Evidence: 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 for assessment of compliance with 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. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. No bioloical data are available for assessment whether the chemical samples comply with the 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.
 
RWQCB Board Decision / Staff Recommendation: After review of 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 no biological data are available for assessment of compliance with the applicable water quality objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10010
 
LOE ID: 21349
 
Pollutant: Total Kjeldahl Nitrogen (TKN)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Robinson Creek under the Region 6 SWAMP program in 2002 and 2003. One of 4 quarterly samples for total Kjeldahl nitrogen was below the detection level. The concentrations in two samples were estimates. The fourth sample had a concentration of 0.16 mg/L.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's 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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly samples were taken between June 2002 and June 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10001
 
Pollutant: Total Nitrogen 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
 
Weight of Evidence: 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. The total nitrogen values in four samples and two annual average datapoints are all estimates, and compliance with the objective cannot be assessed..

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the 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. Four samples and two annual average datapoints are estimated values 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.
 
RWQCB Board Decision / Staff Recommendation: After review of 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 all total nitrogen data are estimated values.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10001
 
LOE ID: 21351
 
Pollutant: Total Nitrogen as N
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Robinson Creek under the Region 6 SWAMP program in 2002 and 2003. Quarterly samples were collected for total Kjeldahl nitrogen and nitrite plus nitrate. Because these constituents included estimated and below detection level values, all four total nitrogen concentrations and both of the annual averages were estimates.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The applicable water quality objective (from Lahontan Basin Plan Table 3-15) includes an annual average total nitrogen concentration of 0.05 mg/L and a 90th percentile value of 0.10 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly sampleseach for total Kjeldahl nitrogen and nitrite plus nitrate were taken between June 2002 and June 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7770
 
Pollutant: Turbidity
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: 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 ollutant. None of the samples exceeds the drinking water maximum contaminant level. However, the minimum sample number requirements of Listing Policy Table 3.2 were not met.

The narrrative turbidity objective is a non-degradation objective and there are too few samples to establsih baseline and trend conditions as required under section 3.10 of the Listing Policy.

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

Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of 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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7770
 
LOE ID: 5025
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured turbidity in 2002 and 2003 under the Region 6 SWAMP program. Four turbidity measurements ranged from <1.0 to 2.8 NTU. The MCL was not violated.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly turbidity measurements were taken in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 5023
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured turbidity in 2002 and 2003 under the Region 6 SWAMP program. Four turbidity measurements ranged from <1.0 to 2.8 NTU.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide narrative turbidity objective 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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly turbidity measurements were taken in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10014
 
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
 
Weight of Evidence: 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. 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.
 
RWQCB Board Decision / Staff Recommendation: After review of 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 are insufficient to document baseline and trend conditions under Listing Policy section 3.10..
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10014
 
LOE ID: 5012
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured pH in 2002 and 2003 under the Region 6 SWAMP program. Four field pH measurements ranged from 5.5 to 7.7 units. One measurement was below 6.5 units.
Data Reference: 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's objective 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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Robinson Creek below Barney Lake, was sampled.
Temporal Representation: Four quarterly pH measurements were taken in 2002 and 2003.
Environmental Conditions: Robinson Creek is a tributary of Bridgeport Reservoir with headwaters near the Sierra Nevada crest. Barney Lake is located within Hoover Wilderness. In addition to the Cold Freshwater Habitat beneficial use, Robinson Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):