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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	Carson River, East Fork
Water Body ID:	CAR6321007219980803164808
Water Body Type:	River & Stream


DECISION ID	7673

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

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. Two lines of evidence, involving a single sample, are available in the administrative record to assess this pollutant. The sample does not exceed the California Toxics Rule (CTR) standards or 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. The single sample did not exceed the CTR standards or the MCL. However, the minium sample number requirements of Table 3.1 of the Listing Policy 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 were not met.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7673


LOE ID:	4889

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

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	1
Number of Exceedances:	0

Data and Information Type:	Not Specified
Data Used to Assess Water Quality:	The U.S Geological Survey sampled arsenic under the Region 6 SWAMP program. One sample had an arsenic concentration of 7.2 ug/L. The CTR standards were not violated.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The California Toxics Rule (CTR) freshwater aquatic life standards for arsenic are as follows: 4-day average = 150 ug/L 1 hour average = 340 ug/L
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS gage below Markleeville, was sampled.
Temporal Representation:	One sample was collected on 11/24/2004.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. Arsenic in this watershed is likely to be from natural volcanic or geothermal sources. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4891

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

Beneficial Use:	Municipal & Domestic Supply

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 arsenic under the Region 6 SWAMP program. One sample had an arsenic concentration of 7.2 ug/L. The MCL was not violated.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson 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 arsenic is 10 ug/L (effective November 28, 2008).
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	One sample was collected on 11/24/2004.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. Arsenic in this watershed is likely to be from natural volcanic or geothermal sources. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	7674

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

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. Two lines of evidence are available in the administrative record to assess this pollutant. None of the nine samples exceeds the California State Notification Level. Two annual average datapoints exceed the site-specific water quality objective. Although this satisfies binomial model requirements for listing, listing is not recommended because the small number of samples per year does not capture seasonal and annual variation in flows and constituent concentrations. Also, except for borate fire retardants used in fighting wildfires, boron in this watershed comes from natural sources such as Grover Hot Springs. The overflow from the springs discharges to Hot Springs Creek, then to Markleeville Creek and the East Fork Carson River. 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 9 samples exceeded the California State Notification Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.Two of 4 annual average datapoints exceeded the site-specific objective and this exceeds the allowable frequency in Table3.1. However listing is not recommended because the data are not temporally representative, and boron in this watershed comes almost entirely from natural sources.. 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 one of the applicable water quality standards is not being exceeded and there is insufficient information to determine compliance with the other.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7674


LOE ID:	21492

Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	9
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 boron under the Region 6 SWAMP program between 2002 and 2004. Boron concentrations in nine samples ranged from 16 to 162 ug/L. The criterion was not exceeded.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The California State Notification Level for boron is 1000 ug/L.
Objective/Criterion Reference:	Drinking Water Notification and Response Levels: An overview

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Nine samples were collected between 2002 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. Boron in this watershed is likely to come from natural geothermal sources. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4890

Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	4
Number of Exceedances:	2

Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S Geological Survey sampled boron under the Region 6 SWAMP program between 2002 and 2004. Boron concentrations in nine samples ranged from 16 to 162 ug/L. The annual average objective was exceeded in 2 out of 4 years.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The site-specific water quality objective is an annual average of 0.12 mg/L (= 120 ug/L) with a 90th percentile value of 0.250 mg/L (= 250 ug/L). See Lahontan Basin Plan Table 3-14.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Nine samples were collected between 2002 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. Boron in this watershed is likely to come from natural geothermal sources. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10534

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

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 (MCL). None of the annual average datapoints exceeds the site-specific water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do notsatisfy 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 12 samples exceeded the MC and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. None of 4 annual average datapoints exceeded the site-specific objective; however, this does not meet the minimum sample number requirements of Listing Policy Table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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 one of the applicable water quality standards is not being exceeded and there is insufficient information to determine compliance with the other..

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 10534


LOE ID:	4892

Pollutant:	Chloride
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 chloride under the Region 6 SWAMP program between 2002 and 2005. Chloride concentrations in 12 samples ranged from 0.33 to 4.39 mg/L. Annual average concentrations did not exceed the objective.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The site-specific objectives are an annual average of 4.0 mg/L and a 90th percentile value 6.0 mg/L. See Lahontan Basin Plan Table 3-14.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS gage below Markleeville, was sampled.
Temporal Representation:	Twelve chloride samples were collected over 4 years (2002 to 2005).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4893

Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	12
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 chloride under the Region 6 SWAMP program between 2002 and 2005. Chloride concentrations in 12 samples ranged from 0.33 to 4.39 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituent" objective. The MCL for chloride is 250 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Twelve chloride samples were collected over 4 years (2002 to 2005).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	7709

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

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(s) 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 fourteen samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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 7709


LOE ID:	5728

Pollutant:	Dissolved oxygen saturation
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	14
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 dissolved oxygen under the Region 6 SWAMP program between January 2002 and August 2005. Percent saturation values in 14 quarterly samples ranged from 98 to 130 percent. The objective was not violated. However, sampling frequency was insufficient to define the natural percent saturation regime or to detect change.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The Lahontan Basin Plan's regionwide narrative objective for dissolved oxygen provides that percent saturation shall not be depressed more than 10 percent nor shall the minimum dissolved oxygen concentration be less than 80 percent of saturation.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS gage below Markleeville, was sampled.
Temporal Representation:	Fourteen quarterly measurements of percent saturation were taken over 4 years (2002 to 2005).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10582

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. One of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. The water quality objective calls for at least 5 fecal coliform samples collected within a 30-day period. 3. One of 7 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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 10582


LOE ID:	21493

Pollutant:	Fecal Coliform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	7
Number of Exceedances:	1

Data and Information Type:	Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality:	The U.S Geological Survey sampled the East Fork Carson River under the Region 6 SWAMP program between 2003 and 2005. Six of 7 fecal coliform samples had estimated bacteria counts, and the seventh was reported as greater than 240 colonies per 100 mL, exceeding the objective.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson 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, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Seven samples (1 to 4 per year) were taken between 2003 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	21495

Pollutant:	Fecal Coliform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Water Contact Recreation

Number of Samples:	7
Number of Exceedances:	1

Data and Information Type:	Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality:	The U.S Geological Survey sampled the East Fork Carson River under the Region 6 SWAMP program between 2003 and 2005. Six of 7 fecal coliform samples had estimated bacteria counts, and the seventh was reported as greater than 240 colonies per 100 mL, exceeding the objective.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson 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, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Seven samples (1 to 4 per year) were taken between 2003 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10542

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. 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 26 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 10542


LOE ID:	21486

Pollutant:	Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	16
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 the East Fork Carson River under the Region 6 SWAMP program between 2001 and 2005. One of 16 quarterly samples was an estimated value, and 8 were below the detection level. Concentrations of nitrite plus nitrate in the remaining samples ranged from 0.002 to 0.02 mg/L The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson 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, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen quarterly samples were taken between 2001 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	7710

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. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. None of 14 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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 7710


LOE ID:	4899

Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	14
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 dissolved oxygen under the Region 6 SWAMP program between 2002 and 2005. Dissolved oxygen concentrations in 14 samples ranged from 8.4 to 12.2 mg/L. The objective was not violated.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	For waters designated COLD and SPWN, the 1 day minimum objective is 8 mg/L dissolved oxygen (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, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Fourteen dissolved oxygen measurements were taken over 4 years (2002 to 2005).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10583

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, consisting of a single sample, 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. 3. No biological data are available to determine whether the single sample exceeded the water quality objective. This sample doe not meet the minimum sample number requirement of 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 and 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 10583


LOE ID:	21499

Pollutant:	Phosphate
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 the East Fork Carson River under the Region 6 SWAMP program. A single sample for dissolved PO4 was collected on November 18, 2003. The concentration was 0.019 mg/L.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	There are no site-specific numerical objectives for phosphate for the East Fork Carson River. The regionwide narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	One sample was collected on November 18, 2003.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10584

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. Three of the annual average datapoints exceed the water quality objective. However, listing is not recommended because the data are not temporally representative and because listing would not be required under the Policy if phosphorus were considered to be a "conventional pollutant." The Listing Policy considers "nutrients" to be "toxicants", making them subject to more stringent requirements for listing and delisting than "conventional pollutants." The policy does not formally define nutrients. Phosphorus is a nutrient for aquatic and terrestrial plants, and a few plant species can accumulate phosphorus to toxic levels in tissue. However, it is unscientific to classify the phosphorus compounds naturally present in surface waters as toxicants. Elemental phosphorus is toxic but it is not normally present in nature. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of variation in streamflows and constituent concentrations expected in streams of the Lahontan Region. 3. Three out of 5 annual average datapoints exceeded the site specific objective and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. The phosphorus compounds for which data are available should not be considered toxicants. 5. 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, although the applicable standard is exceeded, the data are not temporally representative.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 10584


LOE ID:	21498

Pollutant:	Phosphorus
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	5
Number of Exceedances:	3

Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S Geological Survey sampled total phosphorus under the Region 6 SWAMP program between 2001 and 2005. Concentrations in 4 of 16 quarterly samples were below the detection level. The remainder of the samples ranged from 0.018 to 0.201 mg/L. Annual averages were below the detection level in 2 of 5 years. Averages in the remaining 3 years ranged from 0.027 to 0.087 mg/L; all three averages exceeded the objective.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The site-specific objective for total phosphorus in the East Fork Carson River includes an annual average of 0.02 mg/L and an annual 90th percentile value of 0.03 mg/L. See Lahontan Basin Plan Table 3-14.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen quarterly samples (1 to 5 per year) were collected between 2001 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	7785

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 16 suspended sediment concentration values and 16 suspended sediment load values calculated from instantaneous discharge measurements. Suspended sediment concentrations and loads are dependent on flows and can change rapidly over a short time during storm or snowmelt runoff events. Quarterly samples are insufficient to capture these short term events and therefore are insufficient to define natural background suspended sediment concentrations and loads, or to detect trends. Listing Policy Section 3.10 requires that natural background conditions be established. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. 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 available information and data do not meet the requirements of Listing Policy section 3.10.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7785


LOE ID:	4907

Pollutant:	Sediment
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	16
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 under the Region 6 SWAMP program and did load calculations based on concurrent flows between 2001 and 2005. Sixteen instantaneous discharge flow measurements ranged from 29 to 2500 cubic feet per second. Suspended sediment concentration in 16 samples ranged from 1 to 297 mg/L. Suspended sediment loads in 16 calculations ranged from 0.08 to 2000 tons per day. (The highest concentration and load occurred during the spring runoff season in May 2005.)
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The narrative objective for suspended sediment in the Lahontan Basin Plan states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen samples were taken, and sixteen load calculations were done, between 2001 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	7675

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 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and specific conductance values in streams of the Lahontan Region. 3. None of 15 samples exceeded the water qualitiy objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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 7675


LOE ID:	4905

Pollutant:	Specific Conductance
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	16
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 under the Region 6 SWAMP program between 2001 and 2005. In 16 field measurements, specific conductance ranged from 48 to 168 uS/cm. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson 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, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen measurements of specific conductance were taken over 5 years (2001 to 2005).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10536

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

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 (MCL). None of the annual average datapoints exceeds the site-specific water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfythe 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 12 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. None of 4 annual average datapoints exceeded the site-specific objective. However, this does not satisfy the minimum sample number requirement of Table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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 one of the applicable water quality standards is not being exceeded and there is insufficient evidence to determine compliance with the other..

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 10536


LOE ID:	4911

Pollutant:	Sulfates
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	12
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 sulfate under the Region 6 SWAMP program between 2002 and 2005. Sulfate concentrations in 12 samples ranged from 1.3 to 14.8 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	California MCLs apply to ambient waters under the Lahontan Basin Plan's Chemical Constituents objective. The MCL for sulfate is 250 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Twelve sulfate samples were collected over 4 years (2002 to 2005) .
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4910

Pollutant:	Sulfates
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	4
Number of Exceedances:	4

Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S Geological Survey sampled sulfate under the Region 6 SWAMP program between 2002 and 2005. Sulfate concentrations in 12 samples ranged from 1.3 to 14.8 mg/L. The annual average objective was exceeded in 4 out of 4 years.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The site-specific objectives for sulfate in the East Fork Carson River are an annual average of 4.0 mg/L and an annual 90th percentile value of 8.0 mg/L. See Lahontan Basin Plan Table 3-14.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Twelve sulfate samples were collected over 4 years (2002 to 2005).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	7676

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 Sections 3.10 and 6.1.5.9.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 7676


LOE ID:	4920

Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	16
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 water temperature under the Region 6 SWAMP program between 2001 and 2005. Temperatures in 16 field measurements ranged from 0 to 17 degrees Celsius.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson 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, below Markleeville, was sampled.
Temporal Representation:	Sixteen temperature measurements were taken over 5 years (2001 to 2005 at 1 to 5 samples per year).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10585

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

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. Five out of five annual average datapoints exceed the site specific water quality objective. However, listing is not recommended because the data are not temporally representative. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of seasonal and annual variability in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Five out of five annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that though this water body is impaired for sediment toxicity, these water body-pollutant combinations should not be placed on the section 303(d) list because, although applicable water quality standards are being exceeded, the data are not temporally representative.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 10585


LOE ID:	4915

Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	5
Number of Exceedances:	5

Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S Geological Survey sampled TDS under the Region 6 SWAMP program between 2002 and 2005. TDS concentrations in 16 samples reported as "residue" ranged from 45 to 118 mg/L. Annual averages (based on 1 to 5 samples per year) ranged from 81 to 112 mg/L. The highest average was based on a single sample. The annual average objective was exceeded in 5 of 5 years. An additional 6 samples reported as "nonfilterable" TDS were collected in 2003 and 2004 (on the same dates as the "residue" samples. Concentrations in four samples were below the detection level; concentrations in the remaining samples were 10 and 93 mg/L.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The site specific objective for Total Dissolved Solids (TDS) is an annual average of 80 mg/L and a 90th percentile value of 100 mg/L (Lahontan Basin Plan Table 3-14).
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen samples reported as "residue" were collected over 5 years (2001 to 2005 at 1 to 5 samples per year). An additional 6 samples reported as "nonfilterable" were collected in 2004 and 2005.)
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4917

Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	16
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 TDS under the Region 6 SWAMP program between 2001 and 2005. TDS concentrations in 16 samples ranged from 45 to 118 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson 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 Total Dissolved Solids (TDS) is 500 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen samples were collected over 5 years (2001 to 2005 at 1 to 5 samples per year).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10543

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 whether of the chemical samples exceeds the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 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 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 fhere 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 10543


LOE ID:	21491

Pollutant:	Total Kjeldahl Nitrogen (TKN)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	16
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 sulfate under the Region 6 SWAMP program between 2001 and 2005. One of 16 quarterly samples for TKN was an estimate; concentrations in the other samples ranged from 0.04 to 0.19 mg/L
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	There is no site-specific numeric objective for Total Kjeldahl Nitrogen (TKN) for the East Fork Carson River. The Lahontan Basin Plan's narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen quarterly samples were collected between 2001 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10587

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. None of the 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. None of 5 annual average datapoints exceeded the site-specific 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 10587


LOE ID:	21497

Pollutant:	Total Nitrogen as N
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	5
Number of Exceedances:	0

Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S Geological Survey sampled total nitrogen under the Region 6 SWAMP program between 2001 and 2005. Concentrations in 9 of 16 quarterly samples were estimated values. The remainder of the samples ranged from 0.063 to 0.15 mg/L. Numerical annual averages could not be calculated for 2001 through 2004 due to the estimated values. The annual average objective was not exceeded.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The site-specific objective for total nitrogen in the East Fork Carson River includes an annual average of 0.20 mg/L and an annual 90th percentile value of 0.30 mg/L. See Lahontan Basin Plan Table 3-14.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Sixteen quarterly samples were collected between 2001 and 2005..
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10679

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. Four lines of evidence are available in the administrative record to assess this pollutant. Separate lines of evidence were prepared for data expressed as NTU and NTRU. The two types of units are measured differently and are not directly comparable. There are no specific state or federal standards or criteria for turbidity expressed as NTRU. Three of the samples expressed as NTU exceed the 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 levels in streams of the Lahontan Region. 3. Three of 12 samples expressed as NTU exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 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 one of the applicable water quality standards is not being exceeded and the data are insufficient to determine compliance with the other.

SWRCB Board Decision / Staff Recommendation:

USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 10679


LOE ID:	21551

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 sampled the East Fork Carson River under the Region 6 SWAMP program between 2004 and 2005. Two of 4 turbidity measurements expressed as NTRU were below the detection level. The others were 2.2 and 40 NTRU. The highest value was recorded during a high flow spring runoff event in May 2005.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	There are no state or federal standards or criteria for turbidity expressed as NTRU for the projection of aquatic life..
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville was sampled.
Temporal Representation:	Four turbidity measurements recorded as NTRU were taken in 2004 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville"station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4922

Pollutant:	Turbidity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	12
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 under the Region 6 SWAMP program between 2001 and 2004. Turbidity in 12 samples ranged from below the detection level to 14 NTU.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The regionwide turbidity objective in the Lahontan Basin Plan states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Twelve turbidity measurements expressed as NTU were between 2001 and 2004 (at 1 to 5 samples per year).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4923

Pollutant:	Turbidity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Municipal & Domestic Supply

Number of Samples:	12
Number of Exceedances:	3

Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S Geological Survey measured turbidity under the Region 6 SWAMP program between 2001 and 2004. Turbidity in 12 samples ranged from below the detection level to 14 NTU..Three of the 12 samples reported as NTU exceeded the MCL.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient surface waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for 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, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Twelve turbidity measurements expressed as NTU were taken between 2001 and 2004..
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


LOE ID:	4903

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 sampled the East Fork Carson River under the Region 6 SWAMP program between 2004 and 2005. Two of 4 turbidity measurements expressed as NTRU were below the detection level. The others were 2.2 and 40 NTRU. The highest value was recorded during a high flow spring runoff event in May 2005.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	There are no state or federal standards or criteria for turbidity expressed as NTRU for the projection of human health.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).

Evaluation Guideline:
Guideline Reference:

Spatial Representation:	One station, East Fork Carson River at USGS Gage below Markleeville was sampled.
Temporal Representation:	Four turbidity measurements recorded as NTRU were taken in 2004 and 2005.
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville"station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):


DECISION ID	10678

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. (A pH range of 6.5 to 8.5 units applies to "all other waters.") Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.

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 establish 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 10678


LOE ID:	4898

Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None

Beneficial Use:	Cold Freshwater Habitat

Number of Samples:	15
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 pH under the Region 6 SWAMP program between 2002 and 2005. In 15 field samples, pH ranged from 7.7 to 8.3 units.
Data Reference:	2007. SWAMP Data for the East Fork and West Fork Carson River Hydrologic Units.

Water Quality Objective/Criterion:	The objective for pH 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, East Fork Carson River at USGS Gage below Markleeville, was sampled.
Temporal Representation:	Fifteen pH measurements were taken over 4 years (2002 to 2005).
Environmental Conditions:	The East Fork Carson River is an interstate river with headwaters near the Sierra Nevada crest and its lowest point in California in an area transitional to the Great Basin ecoregion. The "below Markleeville" station is downstream of subwatersheds contributing acid mine drainage, and downstream of Markleeville Creek, which is affected by geothermal drainage. In addition to the Cold Freshwater Habitat beneficial use, the river is designated for the Spawning, Reproduction and Development and the Rare, Threatened, or Endangered Species uses. The latter use reflects the presence of Lahontan and Paiute cutthroat trout.
QAPP Information:	The quality assurance requirements of the SWAMP QAPP were met.
QAPP Information Reference(s):