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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	Mammoth Creek (Old Mammoth Road to Highway 395)
Water Body ID:	CAR6031005320080816102036
Water Body Type:	River & Stream

DECISION ID	16417
Pollutant:	Metals
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Reason for Delisting:	Change from general pollutant to specific pollutant listing (e.g. metals to copper)
Impairment from Pollutant or Pollution:	Pollutant
Weight of Evidence:	Mammoth Creek as a whole was listed for "Metals" in the early 1990s on the basis of fish tissue data from the State Water Resources Control Board's Toxic Substances Monitoring Program (TSMP). The TSMP results included "Elevated Data Levels" (EDLs) for several metals. EDLs were statistically high compared to other data statewide, but did not exceed human fish consumption criteria, including the then-applicable OEHHA criteria. In 1998 the State Water Board provided the opportunity to remove listings for TSMP data that did not exceed human consumption criteria. Mammoth Creek was not recommended to be delisted for "Metals" at the time because Lahontan Water Board staff wanted to investigate stormwater impacts on the creek. In 2006, the State Water Board listed Mammoth Creek as a whole for mercury due to exceedance of the newer OEHHA "screening value" for tissue. State Board staff did not identify exceedances of human consumption criteria for other metals. For the 2008 assessment cycle, Mammoth Creek has been divided into three segments. No additional new listings for specific metals are being recommended on the basis of tissue or water data. The general "metals" listing for the creek as a whole is not recommended to be carried over to this segment because a specific listing for mercury is in place.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the general water body-pollutant combination "Metals" should not be placed on the section 303(d) list for this segment because a more specific listing for mercury is in place.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 16417

LOE ID:	6963
Pollutant:	Metals
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Not Recorded
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	0
Number of Exceedances:	0
Data and Information Type:	Not Specified
Data Used to Assess Water Quality:	Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference:	Placeholder reference pre-2006 303(d)
Water Quality Objective/Criterion:	Unspecified
Objective/Criterion Reference:	Placeholder reference pre-2006 303(d)
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	Unspecified
Temporal Representation:	Unspecified
Environmental Conditions:	Unspecified
QAPP Information:	Unspecified
QAPP Information Reference(s):

DECISION ID	16242
Pollutant:	Mercury
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Natural Sources
Expected TMDL Completion Date:	2019
Impairment from Pollutant or Pollution:	Pollutant
Weight of Evidence:	Mammoth Creek as a whole was listed in 2006 based on fish tissue samples. The creek was divided into segments for purposes of the 2008 assessment. Since this segment has no fish passage barriers, the earlier fish tissue samples are considered representative of this segment. This pollutant is being considered for removal from the section 303(d) list under section 4.5 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess pollutant. Two tissue samples and four water samples exceed the applicable standards. The water samples are not temporally representative. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the section 303(d) list. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The water data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Two of three tissue samples and 4 of 12 water samples exceeded the applicable standards and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.
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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 16242

LOE ID:	7449
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total mercury in 12 samples ranged from 0.01 to 0.14 ug/L. The USEPA criteria were not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The U.S. Environmental Protection Agency's national freshwater aquatic life criteria (for total mercury) include a 4-day average of 0.77 ug/L and a 1-hour average of 1.4 ug/L.
Objective/Criterion Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected approximately quarterly between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7450
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	12
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total mercury in 12 samples ranged from 0.01 to 0.14 ug/L. Four samples exceeded the California Toxics Rule standard.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule human health standard for consumption of water and organisms is 0.05 ug/L as a 30 day average.
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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected approximately quarterly between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	6960
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Tissue
Matrix:	Tissue
Fraction:	Total
Beneficial Use:	Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples:	3
Number of Exceedances:	2
Data and Information Type:	Not Specified
Data Used to Assess Water Quality:	Two out of 3 samples exceeded. Three filet composite samples of brown trout were collected in 1992, 1995, and 2002. The 1992 and 2002 samples exceeded the guideline (TSMP, 2002).
Data Reference:	CD includes NON-SWAMP data: including TSMP database for years 1992-2002 and Coastal Fish Contamination Program (CFCP) for years 1 and 2. State Water Resources Control Board. Sacramento, CA
Water Quality Objective/Criterion:	Lahontan RWQCB Basin Plan: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:	0.3 ug/g (OEHHA Screening Value) (Brodberg & Pollock, 1999).
Guideline Reference:	Prevalence of Selected Target Chemical Contaminants in Sport Fish From Two California Lakes: Public health designed screening study. Sacramento, CA: Office of Environmental Health Hazard Assessment
Spatial Representation:	Two stations were sampled: 1.3 miles downstream from Old Mammoth Road on Old State Road and between Hwy 395 and frontage road east of Hwy 395.
Temporal Representation:	Samples were collected annually in 1992, 1995, and 2002.
Environmental Conditions:
QAPP Information:	Toxic Substances Monitoring Program 1992-93 and 1994-95 Data Reports. Environmental Chemistry Quality Assurance and Data Report for the Toxic Substances Monitoring Program, 2001-2002. Department of Fish and Game.
QAPP Information Reference(s):
LOE ID:	7448
Pollutant:	Mercury
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 this station under the Region 6 SWAMP program between 2000 and 2005. Concentrations of dissolved mercury in 10 of 16 samples were below the detection level. Three samples were estimated values, and concentrations in the remaining samples ranged from 0.01 to 0.14 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no applicable California or federal aquatic life criteria for dissolved mercury. The U.S. Environmental Protection Agency's national freshwater aquatic life criteria are expressed as total mercury (including inorganic and organic mercury). Total mercury data for this station are assessed in separate Lines of Evidence.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Sixteen samples were collected between 2000 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9624
Pollutant:	Acid Neutralizing Capacity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Weight of Evidence:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Acid Neutralizing Capacity (ANC) is equivalent to alkalinity, and the USEPA "Gold Book" criterion for alkalinity states that it should be greater than 20 mg/L CaCO3 unless natural alkalinity is lower. The ANC in four field samples from this station was greater than 20 mg/L. There is insufficient information to determine the natural range of ANC. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. It is not possible to determine whether the four ANC samples exceed the criterion. The minimum sample number requirements of Table 3.2 of the Listing Policy are not met. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the minimum sample number requirements of the Listing Policy are not met.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9624

LOE ID:	9124
Pollutant:	Acid Neutralizing Capacity
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 this station under the Region 6 SWAMP program. Four field measurements of ANC (by incremental titration) were taken once a year from 2002 to 2005. ANC ranged from 71 to 86 mg/L CaCO3. Two additional laboratory measurements of ANC were taken in 2002 and 2003. ANC values were 74 and 86 mg/L CaCO3.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal standards or criteria for acid neutralizing capacity (ANC) per se. However, ANC is equivalent to alkalinity, and the U.S. Environmental Protection Agency "Gold Book" recommends alkalinity greater than 20 mg/L CaCO3 unless natural alkalinity is lower.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Four annual field measurements of ANC were taken between 2002 and 2005. Two additional laboratory measurements were taken in 2002 and 2003.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9329
Pollutant:	Aluminum
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the freshwater aquatic life criteria 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. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Nnone of 12 dissolved aluminum samples exceeded the U.S.Environmental Protection Agency's aquatic life criteria. None of 12 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 9329

LOE ID:	7439
Pollutant:	Aluminum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved aluminum in 12 samples ranged from 2 to 7 ug/L. The criteria were not violated
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The U.S. Environmental Protection Agency's national water quality criteria for aluminum for the protection of freshwater aquatic life are a 4-day average of 87 ug/L and a 1-hour average of 750 ug/L.
Objective/Criterion Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7440
Pollutant:	Aluminum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total recoverable aluminum in 12 samples ranged from 12 to145 ug/L. The MCLs were not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California primary MCL for aluminum is 1000 ug/L and the secondary MCL is 200 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9633
Pollutant:	Ammonia
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Weight of Evidence:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy in that single annual samples are not representative of the natural variability in the dissolved ammonia regime. 3. None of three samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
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 single annual samples are not temporally representative..
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9633

LOE ID:	21172
Pollutant:	Ammonia
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Dissolved ammonia was reported for samples collected on April 25, 2002, April 22, 2003 and April 26, 2005. Ammonia concentrations in the first two samples were below detection levels. The concentration in the third sample was 0.013 mg/L. The applicable water quality objectives were not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	At the reported water temperatures and pH values for the three sampling dates, the applicable water quality objectives for unionized ammonia (from Lahontan Basin Plan Table 3-3) are 0.092, 0.065 and 0.092 mg/L (one-hour average). The applicable objectives for ionized ammonia are 7.5, 4.5 and 4.2 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Three samples were collected on April 25, 2002, April 22, 2003 and April 26, 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9330
Pollutant:	Antimony
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 samples exceed the applicable standards. 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 12 dissolved antimony samples exceeded the federal aquatic life criteria. None of 12 total antimony samples exceeded the California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9330

LOE ID:	7437
Pollutant:	Antimony
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2004 and 2005. Concentrations of dissolved antimony in 9 of 12 samples were below the detection level. Concentrations in the remaining 3 samples ranged from 0.05 to 0.1 ug/L. The criteria were not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The USEPA Lowest Observed Effect Levels (LOEL) criteria for protection of aquatic life include an acute antimony value of 9000 ug/L, a chronic value of 1600 ug/L and a limit for toxicity to algae of 610 ug/L
Objective/Criterion Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Twin Lakes" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses. .
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7438
Pollutant:	Antimony
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total antimony were below the detection level in 12 of 12 samples. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 antimony is 6 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the "Spawning, Reproduction and Development" and "Migration of Aquatic Organisms" beneficial uses. .
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9331
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 are available in the administrative record to assess this pollutant. None of the samples exceeds the California Toxics Rule (CTR) standards or the 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 14 dissolved arsenic samples exceeded the CTR standards and none of 13 total arsenic samples exceeded the MCL. 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 9331

LOE ID:	7255
Pollutant:	Arsenic
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 this station under the Region 6 SWAMP program between 2001 and 2005. One of 14 dissolved arsenic samples was an estimated value and arsenic concentrations in the other samples ranged from 2 to 4 ug/L. The California Toxics Rule standards were not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule arsenic standards for the protection of freshwater aquatic life are as follows: 4-day average = 150 ug/L 1-hour average = 340 ug/L.
Objective/Criterion Reference:	Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses. Arsenic in this watershed comes from natural volcanic and geothermal sources.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7256
Pollutant:	Arsenic
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	13
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. In 13 samples, concentrations of total arsenic ranged from 2 to 5 ug/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Thirteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. Arsenic in this watershed comes from natural volcanic and geothermal sources.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9332
Pollutant:	Beryllium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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. There are no California or federal standards or criteria for dissolved beryllium None of the samples for total beryllium 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 satisy 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 12 total beryllium 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 there are no applicable water quality standards for dissolved beryllium and the applicable water quality standard for total beryllium is not being exceeded.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9332

LOE ID:	7257
Pollutant:	Beryllium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved beryllium in 12 samples were below the detection level.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no state or federal standards or criteria for dissolved beryllium for the protection of freshwater aquatic life.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7258
Pollutant:	Beryllium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total beryllium in 11 of 12 samples were below the detection level, and the remaining sample was an estimated value. The MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California MCL for beryllium is 4 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9809
Pollutant:	Bicarbonate
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. There are no applicable state or federal water quality criteria for bicarbonate.. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. There are no applicable standards or criteria and the data cannot be assessed using 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 there are no applicable standards or criteria.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9809

LOE ID:	21184
Pollutant:	Bicarbonate
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 this station under the Region 6 SWAMP program. Four field measurements of bicarbonate (by incremental titration) were taken once a year from 2002 to 2005. The resulting concentrations were 89, 105, 87 and 95 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal standards or criteria for bicarbonate.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Four annual field measurements of bicarbonate were taken between 2002 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9472
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 3.2 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 State Notification Level or the site-specific water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 14 samples exceeded the California State Notification Level. None of 5 annual average datapoints exceeded the site-specific objective. 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 9472

LOE ID:	7259
Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
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 this station under the Region 6 SWAMP program between 2001 and 2005. Two of 14 samples had dissolved boron concentrations below the detection level. Five samples were estimated values. Dissolved boron concentrations in the remaining samples ranged from 7.3 to 27 ug/L. The criterion was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California State Notification Level criterion for boron is 1000 ug/L.
Objective/Criterion Reference:	Drinking Water Notification and Response Levels: An overview
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. .
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	9140
Pollutant:	Boron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 this station under the Region 6 SWAMP program between 2001 and 2005. Two of 14 samples had dissolved boron concentrations below the detection level. Five samples were estimated values. Dissolved boron concentrations in the remaining samples ranged from 7.3 to 27 ug/L. The annual average objective was not exceeded..
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site specific objective (from Lahontan Basin Plan Table 3-17) includes an annual average boron concentration of 0.03 mg/L (equivalent to 30 ug/L) and a 90th percentile value of 0.05 mg/L (equivalent to 50 ug/L).
Objective/Criterion Reference:	Compilation of Water Quality Goals
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. .
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9333
Pollutant:	Cadmium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 dissolved cadmium samples exceeds the California Toxics Rule (CTR) standards. None of the total cadmium 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 12 dissolved cadmium samples exceeded the CTR standards. None of 12 total cadmium 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 9333

LOE ID:	7260
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved cadmium in 12 samples were all below the detection level. Per listing policy Section 6.1.5.5 the California Toxics Rule standards are assumed to be attained.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule cadmium standard for protection of freshwater aquatic life is dependent on hardness. At the hardness levels reported for SWAMP samples at this station, the acute toxicity standard ranges from 0.60 to 2.96 ug/L, and the chronic toxicity standard ranges from 0.57 to 1.74 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7263
Pollutant:	Cadmium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total cadmium in 12 samples were all below the detection level. The MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California MCL for cadmium is 5 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Twin Lakes" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9334
Pollutant:	Calcium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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. There are no applicable standards or criteria for calcium. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Because there are no applicable standards or criteria, Table 3.2 of the Listing Policy cannot be used for assessment. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable water quality standards or criteria.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9334

LOE ID:	7252
Pollutant:	Calcium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total calcium in 12 samples ranged from 4.96 to 14.9 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for calcium. It is generally monitored as a component of another water quality parameter such as hardness, Total Dissolved Solids, or Sodium Adsorption Ratio.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected approximately quarterly between August 2001 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7251
Pollutant:	Calcium
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved calcium in 14 samples ranged from 5.2 to15.6 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for calcium. It is generally monitored as a component of another water quality parameter such as hardness, Total Dissolved Solids, or Sodium Adsorption Ratio.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):	2007. Water Quality Control Plan for the Lahontan Region (as amended).

DECISION ID	9335
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 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 22 samples exceeded the MCL. None of 5 annual average datapoints exceeded the site-specific objective. 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 9335

LOE ID:	7454
Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 this station under the Region 6 SWAMP program between 2001 and 2005. Twenty-two chloride samples included four estimated or below detection level values. The remainder ranged from 0.19 to 1.64 mg/L. The annual average objective was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site-specific objective (from Lahontan Basin Plan Table 3-17) includes an annual average chloride concentration of 1.0 mg/L and a 90th percentile value of 1.4 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twenty-two samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7455
Pollutant:	Chloride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	22
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Twenty-two chloride samples included 4 estimated or below detection level values. The remainder ranged from 0.19 to 1.64 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chloride is 250 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twenty-two samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9643
Pollutant:	Chromium (total)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 samples exceed the water quality objective. (All samples were below the detection level.) Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 12 dissolved chromium samples exceeded the California Toxics Rule standards. None of 12 total chromium samples exceeded the California Maximum Contaminant Level. 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 9643

LOE ID:	7262
Pollutant:	Chromium (total)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved chromium in 10 of 12 samples were below the detection level, and the remaining samples were estimated values. The standards were not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule (CTR) standards for dissolved Cr VI for protection freshwater aquatic life include a 4 day average of 11 ug/L and a 1 hour average of 16 ug/L. For Cr III, the CTR standards are dependent on hardness. At the hardness levels reported for this station, the acute (1 hour average) toxicity standard ranges from 121.52 to 467.07 ug/L. The chronic (4-day average) toxicity standard ranges from 39.2 to 151.51 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7261
Pollutant:	Chromium (total)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total recoverable chromium in 12 samples were all below the detection level. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California MCL for chromium is 50 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9336
Pollutant:	Cobalt
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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. There are no applicable California or federal water quality standards or criteria for cobalt. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. There are no applicable standards or criteria, and the data cannot be assessed Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable water quality standards or criteria for cobalt.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9336

LOE ID:	7265
Pollutant:	Cobalt
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total cobalt in 4 of 12 samples were below the detection level. Concentrations in the remaining 8 samples ranged from 0.08 to 0.185 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for cobalt for the protection 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between August 2001 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7264
Pollutant:	Cobalt
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP between 2001 and 2005. Concentrations of dissolved cobalt in 12 samples ranged from 0.02 to 0.058 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for cobalt for the protection 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between August 2001 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9337
Pollutant:	Copper
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 samples exceed the California Toxics Rule (CTR) aquatic life 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. 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 dissolved copper samples exceeded the CTR standards. None of 12 total copper samples exceeded the MCL. 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 9337

LOE ID:	7267
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total recoverable copper in 8 of 12 samples were estimated values and another sample was below the detection level. Total copper concentrations in the remaining samples ranged from 0.6 to 1 ug/L. The MCLs were not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The primary MCL for copper is 1300 ug/L and the secondary MCL is 1000 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7266
Pollutant:	Copper
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Of 12 samples for dissolved copper, 4 were below the detection level, 4 were estimated values, and the remaining samples were ranged from 0.3 to 0.9 ug/L. The CTR standards were not violated
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule (CTR) freshwater aquatic life standards for copper are dependent on hardness. At the hardness levels reported for SWAMP samples at this station, the acute toxicity standard ranges from 2.62 to 9.91 ug/L, and the chronic toxicity standard ranges from 42.98 to 136.62 ug/L
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9479
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 of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. None of 8 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 9479

LOE ID:	9120
Pollutant:	Dissolved oxygen saturation
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	8
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2003 and 2005. Percent saturation of dissolved oxygen in 8 samples ranged from 93 to 110 percent. The limit in the objective was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The Lahontan Basin Plan's narrative objective states that percent saturation shall not be depressed by more than 10 percent and minimum dissolved oxygen concentration shall not be less than 80 percent saturation.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Eight samples were taken between 2003 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9338
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. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and fecal coliform counts in streams of the Lahontan Region. The water quality objective calls for collection of 5 samples in a 30 day period. 3. Two of 5 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 9338

LOE ID:	7444
Pollutant:	Fecal Coliform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Water Contact Recreation
Number of Samples:	5
Number of Exceedances:	2
Data and Information Type:	Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2004 and 2005. Three of five quarterly samples were estimated values. Fecal coliform counts in the remaining two samples were 79 and 41 colonies per 100 mL, in violation of the objective.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Five quarterly samples were collected between July 2004 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7443
Pollutant:	Fecal Coliform
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	5
Number of Exceedances:	2
Data and Information Type:	Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2004 and 2005. Three of five quarterly samples were estimated values. Fecal coliform counts in the remaining two samples were 79 and 41 colonies per 100 mL, in violation of the objective.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Five quarterly samples were collected between July 2004 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9339
Pollutant:	Fluoride
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. One of the annual average datapoints (based on one sample per year) 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 not satisfy the data quantity requirements of section 6.1.5 of the Policy. One sample per year does not capture seasonal and annual variability. 3. None of 3 samples exceeded the MCL. None of 3 "annual averages" based on a single sample 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 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 9339

LOE ID:	7458
Pollutant:	Fluoride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2002 and 2005. (No samples were collected in 2004.) Concentrations of dissolved fluoride in 2 of 3 samples were estimated or below the detection level. The concentration in the remaining sample was 0.1 mg/L. The objective was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site-specific objective (from Lahontan Basin Plan Table 3-17) includes an annual average fluoride concentration of 0.10 mg/L and a 90th percentile value of 0.30 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Three samples (one per year) were collected in 2002, 2003 and 2005..
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7459
Pollutant:	Fluoride
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2002 and 2005. (No samples were collected in 2004.) Concentrations of dissolved fluoride in 2 of 3 samples were estimated or below the detection level. The concentrations in the remaining sample was 0.1 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 fluoride is 2 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Three samples (one per year) were collected in 2002, 2003 and 2005..
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9685
Pollutant:	Hardness
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. There are no applicable state or federal standards or criteria for hardness. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. There are no applicable water quality standards or criteria. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable standards or criteria.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9685

LOE ID:	21176
Pollutant:	Hardness
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
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 this station under the Region 6 SWAMP program between 2001 and 2005.. Calculated hardness for 14 samples ranged from 17..64 to 72.39 mg equivalent CaCO3/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no state or federal standards or criteria for hardness. Hardness is monitored for purposes such as determination of the applicable criteria and standards for metals whose toxicity is hardness-dependent. The U.S. Environmental Protection Agency's 1986 "Gold Book" includes generally accepted categories of hardness. Calcium and magnesium are the major ions contributing to hardness, and hardness is generally expressed as calcium carbonate. Water with a hardness of 0 to 75 mg equivalent CaCO3/L is considered "soft."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Hardness was calculated for 14 samples collected between 2001 and 2005..
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	9126
Pollutant:	Hardness
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
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 this station under the Region 6 SWAMP program between 2001 and 2005.. Calculated hardness for 14 samples ranged from 17..64 to 72.39 mg equivalent CaCO3/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no state or federal standards or criteria for hardness. Hardness is monitored for purposes such as determination of the applicable criteria and standards for metals whose toxicity is hardness-dependent. The U.S. Environmental Protection Agency's 1986 "Gold Book" includes generally accepted categories of hardness. Calcium and magnesium are the major ions contributing to hardness, and hardness is generally expressed as calcium carbonate. Water with a hardness of 0 to 75 mg equivalent CaC03/L is considered "soft."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Hardness was calculated for 14 samples collected between 2001 and 2005..
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9340
Pollutant:	Iron
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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. Two of the samples exceed the California Maximum Contaminant Level (MCL). However, listing is not recommended because the data are not temporally representative. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full seasonal and annual range of variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Two of 12 samples exceeded the MCL and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
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 one of the applicable water quality standards is being exceeded, the data are not temporally representative.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9340

LOE ID:	7269
Pollutant:	Iron
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	12
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 this station under the Region 6 SWAMP program between 2001 and 2005. Total recoverable iron concentrations in 12 samples ranged from 50 to 340 ug/L. Two of these 12 samples exceeded the State MCL.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 iron is 300 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7268
Pollutant:	Iron
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 this station under the Region 6 SWAMP program between 2001 and 2005. Dissolved iron concentrations in 2 of 14 samples were estimated values. The remainder of the samples ranged from 12 to 46 ug/L. The criterion was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The U.S. Environmental Protection Agency's national freshwater aquatic life criterion for iron is a 4-day average of 1000 ug/L.
Objective/Criterion Reference:	National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9481
Pollutant:	Lead
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 dissolved lead samples exceeds the California Toxics Rule (CTR) standards. None of the total lead 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 12 dissolved lead samples exceeded the CTR standards. None of 12 total lead samples exceeded the MCL. 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 9481

LOE ID:	7270
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Dissolved lead concentrations in 11 of 12 samples were below the detection level, and the remaining sample was an estimated value. The standards were not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule freshwater aquatic life standards for lead are dependent on hardness. At the hardness levels reported for SWAMP samples from this station, the acute toxicity standard ranges from 7.09 to 42.80 ug/L, and the chronic toxicity standard ranges from 0.28 to 1.67 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Hwy 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7271
Pollutant:	Lead
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Of 12 samples, 4 were below the detection level, one was an estimated value, and the remainder had total lead concentrations ranging from 0.09 to 0.37 mg/L. The MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for lead is 15 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Hwy 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9693
Pollutant:	Lithium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Weight of Evidence:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. There are no applicable standards or criteria for lithium. 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. One sample per year is not reqpresentative of seasonal and annual variability. 3. There are no applicable water quality standards or criteria and the data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable standards or criteria.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9693

LOE ID:	7446
Pollutant:	Lithium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2002 and 2004. Concentrations of dissolved lithium in 3 samples ranged from 27.8 to 31.1 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for lithium for the protection 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Three annual samples were collected between 2002 and 2004.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9478
Pollutant:	Magnesium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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. There are no applicable state or federal standards or criteria for magnesium. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. There are no applicable standards or criteria, and the data cannot be assessed using 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 there are no applicable water quality standards or criteria.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9478

LOE ID:	7253
Pollutant:	Magnesium
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved magnesium in 14 samples ranged from 1.13 to 8.12 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for magnesium. It is generally monitored as a component of another water quality parameter such as hardness, Total Dissolved Solids, or Sodium Adsorption Ratio.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7254
Pollutant:	Magnesium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total magnesium in 12 samples ranged from 1.16 to 7.33 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for magnesium. It is generally monitored as a component of another water quality parameter such as hardness, Total Dissolved Solids, or Sodium Adsorption Ratio.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9482
Pollutant:	Manganese
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. There are no applicable standards for protection of the aquatic life use. Five of the samples exceed the California Maximum Contaminant Level (MCL). However, listing is not recommended because the data are not temporally representative. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used 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 expected in streams of the Lahontan Region. 3. Five of 12 samples exceeded the MCL and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
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 one of the applicable water quality standards is being exceeded, the data are not temporally representative.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9482

LOE ID:	7272
Pollutant:	Manganese
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 this station under the Region 6 SWAMP program between 2001 and 2005. One of 14 samples was an estimated value. Concentrations of dissolved manganese in the remaining samples ranged from 1.1 to 9.5 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no state or federal standards or criteria for manganese for the protection of freshwater aquatic life.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7274
Pollutant:	Manganese
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	12
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total manganese ranged from 9 to 124 ug/L. Five of 12 samples exceeded the MCL.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 manganese is 50 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9483
Pollutant:	Molybdenum
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 3.2 a single line of evidence is necessary to assess listing status. Two of evidence are available in the administrative record to assess this pollutant. There are no applicable standards or criteria for molybdenum.. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. There are no applicable standards or criteria and the data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable water quality standards or criteria..
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9483

LOE ID:	7277
Pollutant:	Molybdenum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved molybdenum in 12 samples ranged from 3.2 to 4.7 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for molybdenum for the protection 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between August 2001 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7278
Pollutant:	Molybdenum
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total molybdenum in 12 samples ranged from 3.1 to 4.7 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no applicable water quality standards or criteria for molybdenum for protection of the Municipal and Domestic Supply use.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9484
Pollutant:	Nickel
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 dissolved nickel samples exceeds the California Toxics Rule (CTR) standards. None of the total nickel samples exceeds the 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 12 dissolved nickel samples exceeded the CTR standards. None of 12 total nickel samples exceeds the MCL. 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 9484

LOE ID:	7279
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved nickel in 3 of 12 samples were below the detection level. The remaining samples had dissolved nickel concentrations ranging from 0.18 to 0.28 ug/L. The CTR standards were not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule (CTR) nickel standards for protection of freshwater aquatic life are dependent on hardness. At the hardness levels reported for SWAMP samples at this station, the acute toxicity standard ranges form 107.9 to 326.25 ug/L, and the chronic toxicity standard ranges from 12.00 to 39.61 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7280
Pollutant:	Nickel
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total nickel in 4 of 12 samples were below the detection level. Concentrations in the remaining 8 samples ranged from 0.26 to 0.47 ug/L. The MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nickel is 100 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9470
Pollutant:	Nitrate
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 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 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 16 samples exceeded the MCL. None of 5 annual average datapoints exceeds 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 9470

LOE ID:	9135
Pollutant:	Nitrate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 this station under the Region 6 SWAMP program between 2001 and 2005. Sixteen calculations for nitrate were done using reported values for nitrite and nitrite plus nitrate. Calculated concentrations of nitrate "as N" included 6 estimated values. The remainder of the nitrate values ranged from 0 to 0.064 mg/L. Calculated annual averages for nitrate "as N" included three estimated values. The averages for 2004 and 2005 were 0.021 and 0.019 mg/L. Expressed "as nitrate" the averages were 0.095 and 0.086 mg/L. The objective was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site specific objective for this station (from Lahontan Basin Plan Table 3-17) includes an annual average "nitrate as nitrate" concentration of 0.4 mg/L and a 90th percentile value of 0.8 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Sixteen calculations for nitrate concentration were done using 16 samples each for nitrite and nitrate plus nitrite collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	9134
Pollutant:	Nitrate
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 this station under the Region 6 SWAMP program between 2001 and 2005. Sixteen calculations for nitrate were done using reported values for nitrite and nitrite plus nitrate. Calculated concentrations of nitrate "as N" included 6 estimated values. The remainder of the nitrate values ranged from 0 to 0.064 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 nitrate is 45 mg/L expressed "as nitrate", equivalent to 10 mg/L expressed "as N."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Sixteen calculations for nitrate concentration were done using 16 samples each for nitrite and nitrate plus nitrite collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9471
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.. 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 16 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 9471

LOE ID:	9133
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 this station under the Region 6 SWAMP program between 2001 and 2005. Sixteen samples included one below the detection level and three estimated values. The remainder ranged from 0.001 to 0.066 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Sixteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9473
Pollutant:	Nitrite
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 17 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 9473

LOE ID:	9132
Pollutant:	Nitrite
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	17
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Seventeen quarterly nitrite samples included 8 values below the detection level. The remainder ranged from 0.01 to 0.015 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite is 1 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Seventeen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9474
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. Four of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. Four of 15 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
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 9474

LOE ID:	7250
Pollutant:	Oxygen, Dissolved
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	15
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 this station under the Region 6 SWAMP program between 2001 and 2005. The dissolved oxygen concentrations in 15 samples ranged from 6.6 to 11.1 mg/L. Four samples were below the 8 mg/L minimum concentration.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The objective, from Lahontan Basin Plan Table 3-6, is a one- day minimum dissolved oxygen concentration of 8 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Fifteen samples were collected between 2001 and 2005. Sampling was quarterly between April 2003 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9710
Pollutant:	Phosphate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Weight of Evidence:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Two of the annual average datapoints (based on only 1 to 4 samples per year) exceed the 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 variation expected in streamflows and constituent concentrations in streams of the Lahontan Region.. 3. Two of four annual average datapoints exceeded the site-specific water quality objective and thist exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
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 being exceeded, the data are not temporally representative.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9710

LOE ID:	9139
Pollutant:	Phosphate
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2002 and 2005. Concentrations of PO4-P in 15 samples ranged from 0.016 to 0.055 mg/L. Calculated PO4 concentrations ranged from 0.049 to 0.981 mg/L. Annual average concentrations of PO4 (based on 1 to 4 samples per year) ranged from 0.09 to 0.325 mg/L. The objective was exceeded in 2 of 4 years. An additional sample for hydrolyzable P was collected in November 2001; the concentration was 0.03 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site-specific objective for dissolved orthophosphate at this station (from Lahontan Basin Plan Table 3-17) includes an annual average of 0.11 mg/L and a 90th percentile value of 0.22 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Fifteen samples for PO4-P were collected between 2002 and 2005. An additional sample for hydrolyzable P was collected in November 2001.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9711
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. There is no site-specific objective for total phosphorus and no biological data are available to determine whether the biostimulatory substances objective is being exceeded.. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. No biological data are available to determine whether the objective for biostimulatory substances is being exceeded. The chemical data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because no biological data are available for use in assessing compliance with the objective.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9711

LOE ID:	9138
Pollutant:	Phosphorus
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 sampled this station under the Region 6 SWAMP program between 2002 and 2005 Concentrations of total phosphorus in 12 samples ranged from 0.038 to 0.08 mg/L. No biological data were available for assessment of compliance with the objective for biostimulatory substances.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There is no site-specific numeric objective for total phosphorus for Mammoth Creek. 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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2002 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9476
Pollutant:	Potassium
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. There are no applicable state or federal standards or criteria for potassium. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. There are no applicable water quality standards or criteria and the data cannot be assessed using 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 there are no applicable water quality standards or criteria..
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9476

LOE ID:	9131
Pollutant:	Potassium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Concentrations of dissolved potassium in three samples ranged from 2.09 to 2.62 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no applicable state or federal standards or criteria for potassium for protection 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, "Mammoth Creek at Twin Lakes" was sampled.
Temporal Representation:	Three samples (one per year) were collected in 2002, 2003 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7428
Pollutant:	Potassium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Concentrations of dissolved potassium in three samples ranged from 2.09 to 2.62 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no applicable state or federal standards or criteria for potassium for protection 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, "Mammoth Creek at Twin Lakes" was sampled.
Temporal Representation:	Three samples (one per year) were collected in 2002, 2003 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9812
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 8 suspended sediment load values calculated from instantaneous discharge measurements. Suspended sediment concentrations and loads are dependent on flows and can change rapidly over a short time during storm or snowmelt runoff events. Quarterly samples are insufficient to capture these short term events and therefore are insufficient to define natural background suspended sediment concentrations and loads, or to detect trends. Listing Policy Section 3.10 requires that natural background conditions be established. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy Section 3.10. 3. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the data are insufficient to establish baseline conditions and detect trends as required under section 3.10 of the Listing Policy.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9812

LOE ID:	7447
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of suspended sediment in 16 samples 1 to 14 mg/L. The USGS did 8 sediment discharge (load) calculations using flow (discharge) measurements taken concurrently with the sediment samples between 2003 and 2005. Measured flows during this period ranged from 6.6 to 75 cubic feet per second. Calculated sediment discharge ranged from 0.04 to 2.8 tons per day.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The Lahontan Basin Plan's objective states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Sixteen samples were collected between 2001 and 2005
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9485
Pollutant:	Selenium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 dissolved selenium samples exceeds the California Toxics Rule (CTR) standards. None of the total selenium 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 12 dissolved selenium samples exceeded the CTR standards. None of 12 total selenium samples exceeded the MCL. 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 9485

LOE ID:	7441
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved selenium in 11 of12 samples were below the detection level and the remaining sample was an estimated value. The California Toxics Rule standards were not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule selenium standards for the protection of freshwater aquatic life are as follows: 4-day average = 5.0 ug/L; 1-hour average = 20 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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7442
Pollutant:	Selenium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Eight of 12 samples for total selenium were below detection levels, and 4 of 12 were estimated values. The MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for selenium is 50 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9477
Pollutant:	Silica
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. There are no applicable state or federal standards or criteria for silica. 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. Four samples collected over four years do not capture seasonal and annual variability. 3. There are no applicable standards or criteria and the data cannot be assessed using 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 there are no applicable standards or criteria.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9477

LOE ID:	7451
Pollutant:	Silica
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved silica in 4 samples ranged from 22.7 to 30.4 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal water quality standards or criteria for silica for the protection 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, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Four samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9486
Pollutant:	Silver
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 dissolved silver samples exceeds the California Toxics Rule (CTR) standard. None of the total silver 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 12 dissolved silver samples exceeded the CTR standard. None of 12 total silver samples exceeded the MCL. 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 9486

LOE ID:	7430
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total silver in 12 samples were below the detection level. Per Listing Policy section 6.1.5.5, the MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 silver is 100 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7429
Pollutant:	Silver
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved silver in 12 samples were below the detection level. Per Listing Policy Section 6.1.5.5, the CTR standards were not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule freshwater aquatic life standard for silver is dependent on hardness. At the hardness levels observed in SWAMP samples for this station, the standard ranges from 0.17 to 1.98 ug/L as an instantaneous maximum.
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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9493
Pollutant:	Sodium
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. There are no aquatic standards for sodium and none of the samples exceeds the applicable drinking water criterion.. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of 3 samples exceeded the criterion 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 it cannot be determined if applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9493

LOE ID:	9127
Pollutant:	Sodium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
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 sodium at this station under the Region 6 SWAMP program in 2002, 2003, and 2005. Sodium concentrations ranged from 8.96 to 11.2 mg/L. The criterion was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The U.S. Environmental Protection Agency's Drinking Water Health Advisory criterion for sodium is 20 mg/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, Mammoth Creek at Highway 35, was sampled.
Temporal Representation:	Three samples (one per year) were taken in 2002, 2003, and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7426
Pollutant:	Sodium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
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 sodium at this station under the Region 6 SWAMP program in 2002, 2003, and 2005. Sodium concentrations ranged from 8.96 to 11.2 mg/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no applicable state or federal standards for sodium for the protection of aquatic life.
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, Mammoth Creek at Highway 35, was sampled.
Temporal Representation:	Three samples (one per year) were taken in 2002, 2003, and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9475
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 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 dissolved ion concentrations in streams of the Lahontan Region. 3. None of 23 samples exceeded the MCL 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 9475

LOE ID:	7445
Pollutant:	Specific Conductance
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	23
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Specific conductance in 23 quarterly field measurements ranged from 55 to 193 uS/cm. Specific conductance was also measured in the laboratory for 7 samples; the results ranged from 70 to 200 uS/cm. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twenty-three field measurements of specific conductance were taken quarterly from 2001 to 2005. Seven laboratory measurements were taken during this period..
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9492
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. One of the samples (or annual average datapoints) exceeds the site-specific water quality objective. 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. One of 3 annual average datapoints (based on a single sample) exceeded the site-specific objective. None of 3 samples exceeded the MCL. This does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy; however, the minimum sample number requirementsof Table 3.2 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 9492

LOE ID:	7457
Pollutant:	Sulfates
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	3
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2004.) Sulfate concentrations in five samples ranged from 5.1 to 6.4 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for sulfate is 250 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Three samples (one sample per year) were collected in 2002, 2003 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7456
Pollutant:	Sulfates
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	3
Number of Exceedances:	1
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2000 and 2005. (No samples were collected in 2004.) Sulfate concentrations in three samples ranged from 5.1 to 6.4 mg/L. One of three annual "averages" (based on one sample per year) exceeded the objective.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site-specific objective from Basin Plan Table 3-17 includes an annual average sulfate concentration of 6.0 mg/L and a 90th percentile value of 11.0 mg/L
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Three samples (one sample per year) were collected in 2002, 2003 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9705
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 3 to 6 times per year, 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 the requirements of Listing Policy sections 3.10 and 6.1.5.9 are not met..
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9705

LOE ID:	7249
Pollutant:	Temperature, water
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	22
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Water temperatures in 22 measurements ranged from 0 to 17 degrees Celsius.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The applicable language from the Lahontan Basin Plan's temperature objective 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."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twenty-two temperature measurements were taken between August 2001 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9489
Pollutant:	Thallium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 dissolved thallium samples exceeds the federal aquatic life criteria. None of the total thallium 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 12 dissolved thallium samples exceeded the federal criteria. None of 12 total thallium samples exceeded the MCL. 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 9489

LOE ID:	7275
Pollutant:	Thallium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved thallium in 12 samples were below the detection level. Per Listing Policy section 6.1.5.5, the MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The U.S. Environmental Protection Agency's Lowest Observed Effect Levels (LOEL) criteria include an acute toxicity value of 1400 ug/L,and a chronic toxicity value of 40 ug/L. The criteria also include an "Other" limit of 20 ug/L based on 2600 hour exposure of one fish species..
Objective/Criterion Reference:	Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7276
Pollutant:	Thallium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total recoverable thallium in 12 samples were below the detection level. Per Listing Policy section 6.1.5.5, the MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 thallium is 2 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9488
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. None of the samples exceeds the California Maximum Contaminant Level (MCL). Five annual average datapoints exceed the site-specific water quality objective. However, listing is not recommended because the samples 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 expected in streams of the Lahontan Region. 3. None of 17 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five out of five annual average datapoints exceeded the site-specific objective. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because, although one of the applicable standards is being exceeded, the data are not temporally representative.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9488

LOE ID:	7453
Pollutant:	Total Dissolved Solids
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total Dissolved
Beneficial Use:	Municipal & Domestic Supply
Number of Samples:	17
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of TDS in 17 samples ranged from 49 to 130 mg/L. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The recommended 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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Seventeen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7452
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 this station under the Region 6 SWAMP program. Concentrations of TDS in 17 samples ranged from 49 to 130 mg/L. Annual averages ranged from 81 to 94 mg/L. The annual average objective was exceeded in 5 out of 5 years.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site-specific objective from Lahontan Basin Plan Table 3-17 includes an annual average Total Dissolved Solids (TDS) concentration of 75 mg/L and a 90th percentile value of100 mg/L
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Seventeen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9718
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. There is no site-specific objective for Total Kjeldahl Nitrogen and no biological data are available for assessment of compliance with the water quality objective for biostimulatory substances.. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. There are no biological data available to assess whether the chemical data comply with the objective, and the chemical data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no biological data available for assessment of compliance with the objective.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9718

LOE ID:	9137
Pollutant:	Total Kjeldahl Nitrogen (TKN)
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005 Concentrations of TKN in 14 samples ranged from 0.05 to 0.27 mg/L. No biological data were available for assessment of compliance with the objective for biostimulatory substances.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There is no site-specific numeric objective for Total Kjeldahl Nitrogen (TKN) for Mammoth Creek. 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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Fourteen samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9810
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 site-specific water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 4 annual average datapoints exceeded the site-specific water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9810

LOE ID:	9136
Pollutant:	Total Nitrogen as N
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	4
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Total nitrogen concentrations were calculated for 11 samples collected between 2002 and 2005. Concentrations ranged from 0.086 to 0.281 mg/L. The annual average objective was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The site specific objective for this station (from Lahontan Basin Plan Table 3-17) includes an annual average total nitrogen concentration of 0.6 mg/L and a 90th percentile value of 1.0 mg/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Total nitrogen was calculated from its constituents for 11 samples collected between 2002 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9813
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 sections 3.2 and 3.10 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Separate lines of evidence were prepared to assess data expressed as NTU and NTRU, since the two types of units reflect different optical properties and are not directly comparable. None of the twelve samples expressed as NTU exceeds the California Maximum Contaminant Level (MCL) applicable under the water quality objective for Chemical Constituents. The MCL is expressed as NTU, and the four samples expressed as NTRU cannot be used to determine compliance with the MCL. The Lahontan Basin Plan's narrative objective for turbidity is antidegradation- based and allows no more than a 10 percent increase over natural turbidity levels. Listing Policy Section 3.10 provides direction for assessment of trends in water quality, including a requirement to document background conditions. Turbidity varies with streamflow and can change drastically over a single day depending on storm or snowmelt events. Continuous measurements of turbidity would be necessary to establish natural background conditions and detect trends of increased turbidity in violation of the objective. Quarterly samples are inadequate to determine complince with the narrative objective 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 in streams of the Lahontan Region. 3. None of twelve measurements expressed as NTU exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Sampling frequency was insufficient to define background conditions or detect changes (if changes occurred). Therefore there is insufficient information to assess compliance with the narrative turbidity objective under Listing Policy Section 3.10. 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 one of the applicable standards is not being exceeded and the data are insufficient to determine compliance with the other standard under Listing Policy section 3.10..
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9813

LOE ID:	21188
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 this station under the Region 6 SWAMP program in 2004 and 2004.. Four turbidity measurements expressed as NTRU were all below the detection level.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no state or federal standards or criteria for turbidity expressed as NTRU for the protection of human health.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Four turbidity measurements reported as NTRU were taken 2004 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	21187
Pollutant:	Turbidity
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
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 this station under the Region 6 SWAMP program between 2001 and 2004. Of 12 turbidity measurements reported as NTU, two were below the detection level. The remaining turbidity values ranged from 0.9 to 3.7 NTU. The MCL was not exceeded.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for turbidity is 5 NTU.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twleve turbidity measurements reported as NTU were taken between 2001 and 2004.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	21186
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 sampled this station under the Region 6 SWAMP program between 2001 and 2004. Of 12 turbidity measurements reported as NTU, two were below the detection level. The remaining turbidity values ranged from 0.9 to 3.7 NTU.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The Lahontan Basin Plan's regionwide water quality objective states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Twleve turbidity measurements reported as NTU were taken between 2001 and 2004.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	21189
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 this station under the Region 6 SWAMP program in 2004 and 2004.. Four turbidity measurements expressed as NTRU were all below the detection level.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no state or federal standards or criteria for turbidity expressed as NTRU for the protection of aquatic life..
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Four turbidity measurements reported as NTRU were taken 2004 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9480
Pollutant:	Vanadium
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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. There are no applicable standards or criteria for dissolved vanadium. None of the total vanadium samples exceeds the California State Notification Level criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. There are no applicable standards or criteria for dissolved vanadium. None of 12 total vanadium samples exceeded the California State Notification Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9480

LOE ID:	7433
Pollutant:	Vanadium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved vanadium in 4 of 12 samples were below the detection level. Vanadium concentrations in the remaining 8 samples ranged from 0.4 to 0.8 ug/L.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	There are no California or federal standards or criteria for dissolved vanadium for the protection of freshwater aquatic life.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7434
Pollutant:	Vanadium
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total vanadium in 6 of 12 samples were below the detection level. The presence of vanadium in the remaining 6 samples was verified but not quantified. The criterion was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Notification Level criterion for vanadium in drinking water is 50 ug/L.
Objective/Criterion Reference:	Drinking Water Notification and Response Levels: An overview
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9487
Pollutant:	Zinc
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
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 dissolved zinc samples exceeds the California Toxics Rule (CTR) standards. None of the total zinc 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 12 dissolved zinc samples exceeded the CTR standards. None of 12 total zinc samples exceeded the MCL. 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 9487

LOE ID:	7435
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Dissolved
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 sampled this station under the Region 6 SWAMP program between 2001 and 2005. Two of 12 samples for dissolved zinc were below the detection level, and 3 were estimated values. Concentrations of dissolved zinc in the remaining samples ranged from 0.6 to 2 ug/L. The CTR standards were not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	The California Toxics Rule freshwater aquatic life standards for zinc are dependent on hardness. At the hardness levels reported for SWAMP samples at this station, the acute toxicity standard ranges from 26.94 ug/L to 89.12 ug/L, and the chronic toxicity standard ranges from 27.16 ug/L to 89.85 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, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
LOE ID:	7436
Pollutant:	Zinc
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	Total
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 this station under the Region 6 SWAMP program between 2001 and 2005. Of 12 samples for total recoverable zinc, one was below the detection level and 5 were estimated values. Concentrations of total recoverable zinc in the remaining 6 samples ranged from 1 to 3 ug/L. The MCL was not violated.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
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 zinc is 5 mg/L, equivalent to 5000 ug/L.
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, Mammoth Creek at Highway 395, was sampled.
Temporal Representation:	Twelve samples were collected between 2001 and 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID	9706
Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant
Weight of Evidence:	The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.
RWQCB Board Decision / Staff Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the data are insufficient to establish baseline-trend conditions as required under Listing Policy Section 3.10.
SWRCB Board Decision / Staff Recommendation:
USEPA Decision:

Lines of Evidence (LOEs) for Decision ID 9706

LOE ID:	9122
Pollutant:	pH
LOE Subgroup:	Pollutant-Water
Matrix:	Water
Fraction:	None
Beneficial Use:	Cold Freshwater Habitat
Number of Samples:	17
Number of Exceedances:	0
Data and Information Type:	Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality:	The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Field pH in 17 measurements ranged from 7.6 to 8.5 units. The pH in an additonal 6 laboratory measurements ranged from 7.8 to 8.2 units.
Data Reference:	2007. SWAMP Data for the Owens Hydrologic Unit
Water Quality Objective/Criterion:	.The Lahontan Basin Plan's objective for pH states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference:	2007. Water Quality Control Plan for the Lahontan Region (as amended).
Evaluation Guideline:
Guideline Reference:
Spatial Representation:	One station, "Mammoth Creek at Hwy 395" was sampled.
Temporal Representation:	Seventeen field pH measurements and 6 laboratory measurements were taken between August 2001 and July 2005.
Environmental Conditions:	Mammoth Creek is a tributary of the Owens River with headwaters near the Sierra Nevada crest. The lower reach of Mammoth Creek is influenced by geothermal springs and is called Hot Creek. In addition to the Cold Freshwater Habitat beneficial use, Mammoth Creek is designated for the Spawning, Reproduction and Development and Migration of Aquatic Organisms beneficial uses.
QAPP Information:	The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):