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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	Virginia Creek
Water Body ID:	CAR6304005220011130105548
Water Body Type:	River & Stream


DECISION ID	9949

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 Virginia 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. The single sample does not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 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 the Listing Policy are not met..

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9949


LOE ID:	21339

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 sampled Virginia Creek under the Region 6 SWAMP program. The ANC of one sample collected on March 10, 2003 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	One sample was collected on March 10, 2003
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7773

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 exceed the applicable water quality objectives. 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 ammonia concentrations in streams of the Lahontan Region. 3. None of four samples exceeded the 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 7773


LOE ID:	6081

Pollutant:	Ammonia
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	4
Number of Exceedances:	0

Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled Virginia Creek four times between June 2002 and June 2003 under the Region 6 SWAMP program. Four ammonia samples were all below the detection level. Per listing policy Section 6.1.5.5, the objectives are presumed to be attained.
Data Reference:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Water Quality Objective/Criterion:	At the pH and temperature levels reported for this station, the applicable ammonia objectives from Basin Plan Table 3-1 are as follows. The 1-hour average objective for unionized ammonia ranges from 0.0182 to 0.159 mg/L NH3. The objective for total ammonia ranges from 10.5 to 31 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were collected in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	9948

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. 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 biological data are available 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 9948


LOE ID:	21340

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 Virginia Creek in 2002 and 2003 under the Region 6 SWAMP program. Two of four samples for dissolved Kjeldahl nitrogen were estimates and the other two were below the detection level.
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:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Spatial Representation:	One station, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were taken in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7601

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. One line of evidence is availabe in the administrative record to assess this pollutant. The single sample doe 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 single sample does not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. The single sample did not exceed the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. The minimum sample number requirement of Table 3.2 is 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 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 7601


LOE ID:	5702

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 Virginia Creek under the Region 6 SWAMP program. Only one fecal coliform sample was collected in June 2002. Its value was less than one colony per 100 mL. 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's 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	One fecal coliform sample was collected in June 2002.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


LOE ID:	5703

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 Virginia Creek under the Region 6 SWAMP program. Only one fecal coliform sample was collected in June 2002. Its value was less than one colony per 100 mL. 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's 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).
	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	One fecal coliform sample was collected in June 2002.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	9950

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 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. 3. None of 4 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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 9950


LOE ID:	21341

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 Virginia Creek in 2002 and 2003 under the Region 6 SWAMP program. Concentrations of nitrite plus nitrate in 3 of 4 samples were estimated values. The concentration in the remaining sample was 0.073 mg/L. 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:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Spatial Representation:	One station, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were taken in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7774

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 to assess whether the chemical samples exceed 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 biological data are available for assessment of compliance with the water quality 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 it cannot be determined if applicable water quality standards are being exceeded.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7774


LOE ID:	6080

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 phosphate in 2002 and 2003 under the Region 6 SWAMP program. Concentrations of phosphate in four samples were all estimated or below detection level values.
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 include a site specific objective for phosphate applicable to Virginia Creek. Compliance with the objective for total phosphorus is assessed in a separate line of evidence. 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were collected.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7775

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 (based on only two samples each) 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 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.

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 7775


LOE ID:	4981

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 phosphorus in 2002 and 2003 under the Region 6 SWAMP program. Concentrations of total phosphorus in four samples ranged from 0.008 to 0.013 mg/L. The annual average objective was not exceeded.
Data Reference:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Water Quality Objective/Criterion:	The site-specific objective for Virginia Creek as a tributary of the East Walker includes an annual average Total P = 0.02 mg/L and a 90th percentile value of 0.03 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were collected.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7789

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 four 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. The data bused 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. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy Section 3.10.. 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 requirements of Listing Policy Section 3.10 are not met.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7789


LOE ID:	4985

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 sampled suspended sediment in 2002 and 2003 under the Region 6 SWAMP program. Concentrations in four suspended sediment samples ranged from 1 to 12 mg/L. This is an insufficient number of samples to permit definition of the range of natural conditions or assessment of effects on beneficial uses.
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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were collected.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7599

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
Sources:	Source Unknown
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. None of the four samples exceed the water quality objective. However, sample numbers do not meet the minimum requirements of Listing Policy Table 3-2. 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.

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 sample numbers do not meet the minimum requirements of Listing Policy Table 3-2..

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7599


LOE ID:	4983

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 field measurements ranged from 56 to 63 uS/cm, and one laboratory measurement was 58 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:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Spatial Representation:	One station, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly field measurements and one laboratory measurement were taken in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7758

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 7758


LOE ID:	4986

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 water temperature in 2002 and 2003 under the Region 6 SWAMP program. Four temperature measurements ranged from 1 to 16 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly temperature measurements were taken in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	9952

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. All of the samples are estimated value. 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 biological data are available to assess compliance with the objective for biostimulatory substances. 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.

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 9952


LOE ID:	21342

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 Virginia Creek in 2002 and 2003 under the Region 6 SWAMP program. One of four samples for total Kjeldahl nitrogen was an estimate, one was below the detection level, and concentrations in the remaining samples were 0.12 and 0.15 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:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Spatial Representation:	One station, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were taken in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	9953

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. All four total nitrogen values and the two annual average datapoints are estimates.. 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. Because the four total nitrogen samples and two annual average datapoints are all estimates, 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 of the data are estimated values..

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9953


LOE ID:	21343

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 Virginia Creek in 2002 and 2003 under the Region 6 SWAMP program. Four samples each were collected for total Kjeldahl nitrogen and nitrite plus nitrate. Because these samples included estimated and below detection level values, all total nitrogen concentrations and the two 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 site-specific objective for Virginia Creek as a tributary of the East Walker includes an annual average Total N concentration of 0.05 mg/L and a 90th percentile value of 0.20 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples each were collected for total Kjeldahl nitrogen and nitrite plus nitrate.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	9951

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 pollutant. None of the samples exceeds the California Maximum Contaminant Level. The Lahontan Basin Plan's narrative turbidity objective is a non-degradation objective, and sample numbers are insufficient to establish baseline conditions or detect trends as required under Listing Policy Section 3.10. 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 turbidity values in streams of the Lahontan Region. 3. None of 4 samples exceeded the Maximum Contaminant Level 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. It is not possible to determine whether the narrative turbidity objective was exceeded because the requirements of Listing Policy Section 3.10 were 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 9951


LOE ID:	4988

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 <0.1 to 2 NTU. 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 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were collected in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


LOE ID:	4987

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 <0.1 to 2 NTU.
Data Reference:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Water Quality Objective/Criterion:	The narrative objective from 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:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were collected in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):


DECISION ID	7600

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 as required under Listing Policy section 3.10.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7600


LOE ID:	4980

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. 4 field pH measurements ranged from 6.5 to 7.8 units.
Data Reference:	2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units.

Water Quality Objective/Criterion:	The regionwide objective in the Lahontan Basin Plan 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, "Virginia Creek at Conway Summit," was sampled.
Temporal Representation:	Four quarterly samples were collected in 2002 and 2003.
Environmental Conditions:	Virginia Creek is a tributary of the East Walker River with headwaters near the Sierra Nevada crest. The Conway Summit station may be affected by runoff from a road that parallels the creek upstream. In addition to the Cold Freshwater Habitat beneficial use, Virginia Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):