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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name:	Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)
Water Body ID:	CAR6031005120080816102743
Water Body Type:	River & Stream


DECISION ID	16418	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 16418, Metals	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

6964

Pollutant:

Metals

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

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

Data Reference:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	16241	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	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 4.1 and 4.5 of the Listing Policy. Under section 4.1 a single line of evidence is necessary to assess listing status. Five lines of evidence are available in the administrative record to assess this pollutant. Two out of three fish tissue samples and 3 out of 10 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 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 quarterly water samples do not capture the full range of seasonal and annual variation in streamflows and constituent concentrations expected in streams of the Lahontan Region. 3. Two out of 3 tissue samples and 3 out of 10 water samples exceed the applicable standards. Sample numbers are insufficient to justify delisting using 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 not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):	USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.

Line of Evidence (LOE) for Decision ID 16241, Mercury	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

9114

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station between 2001 and 2005 under the Region 6 SWAMP program. Concentrations of dissolved mercury in 8 of 10 samples were below the detection level, and a ninth sample was an estimated value. One sample had a dissolved mercury concentraiton of 0.01 ug/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal criteria for dissolved mercury for the protection of aquatic life. The U.S. Environmental Protection Agency's freshwater aquatic life criteria are expressed as total mercury.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 16241, Mercury	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

6961

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

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:

Toxic Substances Monitoring Program data for years 1992-2002 and Coastal Fish Contamination Program for years 1 and 2. State Water Resources Control Board

SWAMP Data:

Non-SWAMP

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:

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):

Line of Evidence (LOE) for Decision ID 16241, Mercury	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

9112

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station between 2001 and 2005 under the Region 6 SWAMP program. One of 10 samples for total mercury was an estimated value. Mercury concentrations in the remaining samples ranged from 0.02 to 0.08 mg/L. Three samples exceeded the CTR standard.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) human health standard for consumption of water and organisms is 0.05 ug/L total mercury 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 Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 16241, Mercury	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

9113

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 16241, Mercury	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

9115

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no state or federal criteria for dissolved mercury for the protection of human health.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9446	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the federal aquatic life criteria or the California primary or secondary Maximum Contaminant Levels (MCLs). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of the samples exceeded the MCLs or the federal freshwater aquatic life criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9446, Aluminum	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7199

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Of 10 dissolved aluminum samples, three were estimated values. The remaining samples had both dissolved aluminum concentrations ranging from 1 to 6 ug/L. The criteria were not violated

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 samples per year) were collected between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 9446, Aluminum	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7200

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total aluminum in 10 samples ranged from 6 to 88 ug/L The MCLs were not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The primary MCL for aluminum is 1000 ug/L and the secondary MCL is 200 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9345	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable criteria and 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 10 dissolved antimony samples exceeded the federal aquatic life criteria. None of 10 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9345, Antimony	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7234

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. All of 10 samples for total antimony were below the detection level. Under Section 6.1.5.5 of the Listing Policy, the MCL is considered to be attained.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for antimony is 6 ug/L.

Objective/Criterion Reference:

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:

Ten 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):

Line of Evidence (LOE) for Decision ID 9345, Antimony	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7233

Pollutant:

Antimony

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved antimony were below detection level in 8 of 10 samples. One sample was an estimated value and the antimony concentration in the remaining sample was 0.1 ug/L.. The criteria were not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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 Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9439	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable water quality standard. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of 10 dissolved arsenic samples exceeded the California Toxics Rule standards. None of 10 total arsenic samples exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9439, Arsenic	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7201

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. One of 10 quarterly samples was an estimated value. Concentrations of dissolved arsenic in the remaining 9 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

SWAMP Data:

SWAMP

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9439, Arsenic	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7202

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. In 10 samples collected approximately quarterly, 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for arsenic is 10 ug/L.

Objective/Criterion Reference:

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:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9346	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. There are no applicable standards or criteria for dissolved beryllium. None of the total beryllium 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 the total beryllium 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9346, Beryllium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7203

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved beryllium in 10 quarterly samples were below the detection level.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoty Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9346, Beryllium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7204

Pollutant:

Beryllium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total beryllium in 9 of 10 samples were below the detection level. The tenth sample was an estimated value.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California MCL for beryllium is 4 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples 1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9420	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the site specific water quality objective or 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. None of 4 samples exceeded the site-specific objective or the California State Notification Level criterion and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9420, Boron	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7206

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between July 28, 2004 and July 21, 2004. The concentration of dissolved boron in one of four samples was below the detection level. Another sample was an estimated value. The dissolved boron concentrations in the two remaining samples were 8.3 and 11 ug/L. The criterion was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Drinking Water Notification and Response Levels: An Overview

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Four samples were collected approximately quarterly 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):

Line of Evidence (LOE) for Decision ID 9420, Boron	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8837

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between July 28, 2004 and July 21, 2005. The concentration of dissolved boron in one of four samples was below the detection level. Another sample was an estimated value. The dissolved boron concentrations in the two remaining samples were 8.3 and 11 ug/L. The site specific objective was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site-specific objective for Mammoth Creek at Highway 395 (in Lahontan Basin Plan Table 3-17) applies to this station through the Tributary Rule. It includes an annual average boron concentration of 0.03 mg/L and a 90th percentile value of 0.05 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Four samples were collected approximately quarterly 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	9348	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples for total or dissolved cadmium exceeds the applicable standard. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used 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 10 dissolved cadmium samples exceeded the California Toxics Rule standards. None of 10 total cadmium 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9348, Cadmium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7207

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved cadmium in 10 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule freshwater aquatic life standards for cadmium are dependent on hardness. At the hardness levels reported for this station, the acute toxicity standard ranges from 0.74 to 2.96 ug/L. The chronic toxicity standard ranges from 0.66 to 1.74 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Twelve samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9348, Cadmium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7208

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total cadmium in 9 of 10 samples were below the detection level. A tenth sample was an estimated value. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The California MCL for cadmium is 5 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9341	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two of evidence are available in the administrative record to assess this pollutant. There are no applicable California or federal 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. 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable California or federal standards or criteria.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9341, Calcium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7194

Pollutant:

Calcium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved calcium in 10 samples ranged from 5.88 to 16.4 mg/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten quarterly samples were collected between August 2000 and July 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9341, Calcium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7195

Pollutant:

Calcium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of total calcium in 10 samples ranged from 5.14 to 17.4 mg/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten quarterly 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):


DECISION ID	9424	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples or annual average datapoints exceeds 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 4 annual average datapoints exceeded the site-specific objective. At least 5 annual average datapoints are needed for assessment with Listing Policy Table 3.2. None of 10 samples exceeded the California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9424, Chloride	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8860

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Ten chloride samples included one estimated and one below detection level value. Concentrations in the remaining samples ranged from 0.24 to 1.06 mg/L. One of four calculated annual averages was an estimated value; the others were 0.51, 0.60 and 0.69 mg/L. The objective was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The applicable site-specific objective (from Basin Plan Table 3-17) includes an annual average chloride concentration of 0.8 mg/L and a 90th percentile value of 1.4 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples each (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 9424, Chloride	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8861

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCLfor chloride is 250 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples each (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9349	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable water quality standard(s). 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 10 dissolved chromium samples exceeded the California Toxics Rule standards. None of 10 total chromium 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9349, Chromium (total)	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7209

Pollutant:

Chromium (total)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved chromium in 10 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule freshwater aquatic life standards for chromium VI are: 4-day average = 11 ug/L; 1 hour average = 16 ug/L). The chromium III standards are hardness dependent. At the hardness levels reported for this station, the acute toxicity standard ranges from 153.50 to 421.35 ug/L. The chronic toxicity standard ranges from 49.80 to 136.68.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Twin Lakes" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2008.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9349, Chromium (total)	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7210

Pollutant:

Chromium (total)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total chromium in 10 quarterly 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chromium is 50 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Twin Lakes" was sampled.

Temporal Representation:

Ten 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):


DECISION ID	9342	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. There are no 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. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 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 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable California or federal standards or criteria.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9342, Cobalt	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7212

Pollutant:

Cobalt

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved cobalt in 10 samples ranged from 0.033 to 0.091 ug/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between August 2001 and July 2005. No samples were collected in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9342, Cobalt	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7211

Pollutant:

Cobalt

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of total cobalt in 2 of 10 samples were below the detection level. Concentrations in the remaining 8 samples ranged from 0.097 to0.259 ug/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):


DECISION ID	9350	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the dissolved copper or total copper samples exceeds the applicable standard(s). 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 10 dissolved copper samples exceeded the California Toxics Rules standards. None of 10 total copper 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9350, Copper	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7214

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total recoverable copper in 3 of 10 samples were below the detection level. Another three samples were estimated values. Concentrations of total copper in the remaining samples ranged from 0.7 to 1.0 ug/L. The MCLs were not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):

Line of Evidence (LOE) for Decision ID 9350, Copper	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7213

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Of 10 samples for dissolved copper, 4 were below the detection level, 4 were estimated values, and dissolved copper concentrations in the remaining samples were 0.3 and 0.9 ug/L. The CTR standards were not violated

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule freshwater aquatic life standards for copper are dependent on hardness. At the hardness levels reported for this station, the acute toxicity standard ranges from 3.10 to 9.92 ug/L, and the chronic toxicity standard ranges from 2.27 to 6.80 ug/L

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9421	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9421, Dissolved oxygen saturation	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7180

Pollutant:

Dissolved oxygen saturation

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2003 and 2005. Percent saturation of dissolved oxygen ranged from 96 to 107 percent. The objective was not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Eight samples were collected approximately quarterly between October 2003 and July 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9425	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Two of evidence are available in the administrative record to assess this pollutant. One of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and fecal coliform counts in streams of the Lahontan Region. 3. One 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9425, Fecal Coliform	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7176

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Water column surveys (e.g. fecal coliform)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2004 and 2005. Bacteria counts in two of five quarterly samples were below the detection level. Two samples were estimated values, and the count in the remaining sample was 44 colonies per 100 mL, in violation of the objective.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock 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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" 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):

Line of Evidence (LOE) for Decision ID 9425, Fecal Coliform	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7177

Pollutant:

Fecal Coliform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

Water column surveys (e.g. fecal coliform)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" 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	9426	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. There are no applicable state or federal standards or criteria 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable state or federal standards or criteria.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9426, Hardness as CaCO3	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8859

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Hardness in 10 samples ranged from 21.11 to 72.43 mg/L CaCO3.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 9426, Hardness as CaCO3	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8858

Pollutant:

Hardness as CaCO3

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9443	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. The aquatic life criterion was not exceeded. Three of the samples exceed the California Maximum Contaminant Level (MCL). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used 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. Three of 10 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. State Board Review and Conclusion: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for iron based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. At the June 15, 2010 State Water Board meeting for approval of the 2010 Integrated Report, the State Water Board directed staff to reevaluate the listing recommendation for this water body-pollutant combination. Based on this reevaluation, State Water Board staff recommended the listing recommendation be revised to not place this water body-pollutant combination on the 303(d) list because the data show that they may not be temporally respresentative because the exceedences occurred in wetter months. On August 4, 2010 the State Water Board approved the staff recommendation to not place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is the same as written under the "Regional Board Conclusion" above.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because, although one of the applicable water quality standards is being exceeded, the data are not temporally representative.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, the State Water Board recommends that this water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are being exceeded.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9443, Iron	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7215

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Dissolved iron concentrations in 10 samples ranged from 15 to 115 ug/L. The criterion was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9443, Iron	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7216

Pollutant:

Iron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005.
Total recoverable iron concentrations in 10 samples ranged from 80 to 400 ug/L. Three samples exceeded the California MCL.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for iron is 300 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):


DECISION ID	9351	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the dissolved lead or total lead samples exceeds the applicable standard(s). 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 10 dissolved lead samples exceeded the California Toxics Rule standards. None of 10 total lead 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9351, Lead	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7218

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Of 10 samples, 3 had concentrations of total lead below the detection level and one was an estimated value. Conentrations in the remaining samples ranged from 0.06 to 0.17 ug/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for lead is 15 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):

Line of Evidence (LOE) for Decision ID 9351, Lead	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7217

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Dissolved lead concentrations in 9 of 10 samples were below the detection level. The remaining sample was an estimated value. The standards were not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule freshwater aquatic life standards for lead are dependent on hardness. At the hardness levels reported for this station, the acute toxicity standard ranges from 8.92 to 42.83 ug/L and the chronic toxicity standard ranges from 0.35 to 1.67 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9343	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. There are no applicable California of federal water quality 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable California or federal standards or criteria.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9343, Magnesium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7197

Pollutant:

Magnesium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved magnesium in 10 samples ranged from 1.56 to 8.19 mg/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten quarterly samples were collected between August 2000 and July 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9343, Magnesium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7196

Pollutant:

Magnesium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of total magnesium in 10 samples ranged from 1.45 to 8.2 mg/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten quarterly 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):


DECISION ID	9353	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. There are no applicable 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 water quality standards or criteria and the data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no applicable water quality standards or criteria.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9353, Molybdenum	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7223

Pollutant:

Molybdenum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved molybdenum in 10 samples ranged from 2 to 2.7 ug/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between August 2001 and July 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9353, Molybdenum	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7224

Pollutant:

Molybdenum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of total molybdenum in 10 samples ranged from 2 to 2.6 ug/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

There are no applicable water quality standards or criteria for molybdenum for protection of the Municipal and Domestic Supply beneficial use.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):


DECISION ID	9447	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable California Toxics Rule standards or 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 10 dissolved nickel samples exceeded the California Toxics Rule standards. None of 10 total nickel 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9447, Nickel	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7226

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005.
Concentrations of total nickel in 2 of 10 samples were below the detection level. Concentrations in the remaining 8 samples ranged from 0.28 to 0.57 ug/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nickel is 100 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Twin Lakes" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 9447, Nickel	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7225

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved nickel in 2 of 10 samples were below the detection level. The remaining samples had dissolved nickel concentrations ranging from 0.22 to 0.32 ug/L. The CTR standards were not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule freshwater aquatic life standards for nickel are dependent on hardness. At the hardness levels reported for this station, the acute toxicity standard ranges from 125.60 to 356.41 ug/L. The chronic toxicity standard ranges from 13.96 to 39.63 ug/L

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9427	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples or annual average datapoints exceeds the applicable 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 10 samples samples exceeded the California Maximum Contaminant Level. None of 4 annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9427, Nitrate	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8851

Pollutant:

Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Nitrate "as N" was calculated from 10 samples each for nitrite and nitrite plus nitrate. The calculations included one below detection level value and one estimated value. Concentrations of nitrate as N in the remaining calculated values ranged from 0 to 0.057 mg/L. When expressed "as nitrate" the maximum value was 0.257 mg/L. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L exprssed "as nitrate." This is equivalent to 10 mg/L expressed "as N."

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples each (1 to 4 per year) were collected for nitrite and nitrite plus nitrate between 2001 and 2005. No samples were collected in 2002.

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):

Line of Evidence (LOE) for Decision ID 9427, Nitrate	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8849

Pollutant:

Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The applicable site-specific objective (from 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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples each (1 to 4 per year) were collected for nitrite and nitrite plus nitrate between 2001 and 2005. No samples were collected in 2002.

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	9428	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the 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 10 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9428, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8845

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. One of 10 samples for nitrite plus nitrate was below the detection level and one was an estimated value. Concentrations in the remaining 8 samples ranged from 0.001 to 0.058 mg/L. the MCL was not exceeded..

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite plus nitrate is 10 mg/L, expressed "as N."

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9435	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

Pollutant:	Nitrite as Nitrite NO2
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One 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 10 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9435, Nitrite as Nitrite NO2	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8844

Pollutant:

Nitrite as Nitrite NO2

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Two of 10 nitrite samples were below the detection level; the remaining samples' nitrite concentrations ranged from 0.001 to 0.002 mg/L. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite is 1 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9422	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Three 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. Three of 9 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9422, Oxygen, Dissolved	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7178

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. The dissolved oxygen concentrations in 9 samples ranged from 6.5 to 10.7 mg/L. Three samples were below the 8 mg/L minimum concentration.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Nine samples were collected approximately quarterly between August 2001 and July 2005. No samples were collected in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9436	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. 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 four annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9436, Phosphate	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8850

Pollutant:

Phosphate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Concentrations of PO4-P in 10 samples ranged from 0.019 to 0.066 mg/L. Calculated PO4 concentrations ranged from 0.058 to 0.202 mg/L. The objective was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The applicable site-specific objective (from Basin Plan Table 3-17) includes an annual average dissolved orthophosphate concentration of 0.27 mg/L and a 90th percentile value of 0.050 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples each (1 to 4 per year) were collected for PO4-P between 2001 and 2005. No samples were collected in 2002.

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	9444	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological data are available for assessment whether any of the chemical 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 do not satisfy the data quality requirements of section 6.1.4 of the Policy due to an error in the SWAMP QAPP regarding holding times for total phosphorus samples.. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. No biological data are available for assessment of compliance with the objective for biostimulatory substances using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there is a quality assurance problem with the chemical data and no biological data are available for assessment of compliance with the water quality objective for biostimulatory substances.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9444, Phosphorus	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8852

Pollutant:

Phosphorus

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total phosphorus ranged from 0.035 to 0.101 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

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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:

Sampling and analysis were done according to the SWAMP QAPP. However, in July 2009 an error was discovered in the QAPP related to holding times for total phosphorus samples that affects the validity of data for the Lahontan Region The holding time for samples that are not acid-preserved.should be 48 hours rather than 28 days as indicated in the QAPP. "Low level" phosphorus analyses, without acid preservation, are used in the Lahontan Region's SWAMP program. .

QAPP Information Reference(s):


DECISION ID	9460	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	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 is available in the administrative record to assess this pollutant. It includes 10 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the requirements of Listing Policy section 3.10 are not met.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9460, Sediment	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8869

Pollutant:

Sediment

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey (USGS) sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. (No samples were collected in 2002.) Suspended sediment concentrations in 10 samples ranged from 2 to 16 mg/L. The USGS calculated sediment loads based on 8 instantaneous discharge flow measurements collected from 2003 to 2005. Flows ranged from 7.3 to 60 cubic feet per second. The associated loads ranged from 0.07 to 0.57 tons per day. The data were not sufficient to document baseline and trend conditions to assess compliance with the objective.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected quarterly in 2001 and from 2003 to 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9354	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable water quality standard. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 10 dissolved selenium samples exceeded the California Toxics Rule standards. None of 10 total selenium 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9354, Selenium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7235

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Concentrations of dissolved selenium in 10 samples were all below the detection levels. The California Toxics Rule standards were not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9354, Selenium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7236

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Ten out of ten samples were below detection levels. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for selenium is 50 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):


DECISION ID	9355	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable water quality standard(s). 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 10 dissolved silver samples exceeded the California Toxics Rule standards. None of 10 total silver 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9355, Silver	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7228

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005.
Concentrations of total silver in 10 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for silver is 100 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):

Line of Evidence (LOE) for Decision ID 9355, Silver	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7227

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved silver in 10 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule freshwater aquatic life standards for silver are dependent on hardness. At the hardness levels reported for this station, the acute toxicity standard (as an instantaneous maximum) ranges from 0.24 to 1.98 mg/L.:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9429	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples 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 10 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9429, Specific Conductance	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8838

Pollutant:

Specific Conductance

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Ten field measurements of specific conductance ranged from 62 to 197 uS/cm. An additional two laboratory measurements taken in 2001 were 163 and 194 uS/cm. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten field measurements were taken approximately quarterly between August 2001 and July 2005. Two additional laboratory measurements were taken in August and November 2001. No measurements were taken in 2002.

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	9423	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	The Lahontan Basin Plan's narrative temperature objective is an antidegradation-based objective that requires that there be no change in temperature in waters designated for the Cold Freshwater Habitat (COLD) beneficial use. The objective does not include specific numerical limits for protection of the COLD use. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough temperature samples to establish baseline conditions (including diel, seasonal, annual and interannual variations in temperature) or to detect declining trends in the temperature regime if such trends exist. Because temperature samples were collected only quarterly, weekly and monthly average data are not available for comparison with guidelines in the scientific literature for the temperature requirements of sensitive aquatic species such as salmonids, as directed in Listing Policy Section 6.1.5.9.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the requirements of Listing Policy sections 3.10 and 6.1.5.9 are not met.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9423, Temperature, water	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7175

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Water temperatures in 9 measurements ranged from 0 to18 degrees Celsius.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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 (5o F) above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Nine temperature measurements were taken approximately quarterly between August 2001 and July 2005. No measurements were taken in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9344	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of available in the administrative record to assess this pollutant. None of the samples for total thallium or dissolved thallium exceeds the applicable criteria or standard. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 10 dissolved thallium samples exceeded the freshwater aquatic life criteria. None of 10 total thallium 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9344, Thallium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7221

Pollutant:

Thallium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005.
Concentrations of total recoverable thallium in 10 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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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 Developmentand Migration of Aquatic Organisms beneficial uses.

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9344, Thallium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7222

Pollutant:

Thallium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for thallium is 2 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):


DECISION ID	9438	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Four annual average datapoints (based on only 1 to 4 samples per year) exceed the site-specific objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 10 samples exceeded the MCL. Four out of 4 annual average datapoints (calculated from only 1 to 4 samples per year) exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9438, Total Dissolved Solids	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7245

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Concentrations of TDS in ten quarterly samples ranged from 44 to 136 mg/L. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The recommended MCL for Total Dissolved Solids (TDS) is 500 mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected approximately quarterly between 2001 and 2005. (No samples were collected in 2002.)

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):

Line of Evidence (LOE) for Decision ID 9438, Total Dissolved Solids	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7240

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. (No samples were collected in 2002.) Concentrations of TDS in 10 samples ranged from
44 to 136 mg/L. Annual averages (calculated from 1 to 4 samples per year) ranged from 97 to 127 mg/L. The annual average objective was exceeded in 4 out of 4 years.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The site-specific objective for Total Dissolved Solids (TDS) at this station (from Lahontan Basin Plan Table 3-17) includes an annual average TDS concentration of 85 mg/L; and a 90th percentile value of 115 mg/L.

Objective/Criterion Reference:

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:

Ten samples (1 to 4 per year) were collected quarterly in 2001 and from 2003 to 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9445	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. There are no biological data available for assessment whether of the chemical samples exceeds the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. There are no biological data available for assessment of compliance with the objective for biostimulatory substances under Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there are no biological data available for assessment of compliance with the water quality objective for biostimulatory substances.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9445, Total Kjeldahl Nitrogen (TKN)	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8846

Pollutant:

Total Kjeldahl Nitrogen (TKN)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of TKN in 10 samples ranged from 0.001 to 0.058 mg/L. No biological data are available for assessment of compliance with the water quality objective for biostimulatory substances.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples (1 to 4 per year) were collected between 2001 and 2005. No samples were collected in 2002.

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	9442	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological data are available for assessment whether any of the samples exceed the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. There are no biological data available for use with the 4 chemical samples to determine compliance with the objective under Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because no biological data are available for assessment of compliance with the objective for biostimulatory substances..

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9442, Total Nitrogen as N	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8848

Pollutant:

Total Nitrogen as N

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) Total nitrogen was calculated from 10 samples each for total Kjeldahl nitrogen (TKN) and nitrite plus nitrate. Two of the calculations were estimated values due to below detection level and estimated values in the basic data. The remainder ranged from 0.100 to 0.258 mg/L total nitrogen. The objective was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The applicable site-specific objective (from 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:

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

2007. SWAMP Data for the Owens Hydrologic Unit

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples each (1 to 4 per year) were collected for TKN and nitrite plus nitrate between 2001 and 2005. No samples were collected in 2002.

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	9440	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Separate lines of evidence were prepared for data expressed as NTU and NTRU. The two types of units are measured differently and are not directly comparable. There are no specific state or federal standards or criteria for turbidity expressed as NTRU. None of the samples expressed as NTU exceed the Maximum Contaminant level. The Lahontan Basin Plan's narrative turbidity objective is a non-degradation objective, and sample numbers are insufficient to establish baseline conditions or detect trends as required under Listing Policy Section 3.10. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy (for samples expressed as NTU). Quarterly samples do not capture the seasonal and annual variability expected in streamflows and turbidity in streams of the Lahontan Region. 3. None of 5 samples expressed as NTU exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. It is not possible to determine whether the narrative turbidity objective was exceeded because the requirements of Listing Policy Section 3.10 were not met. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because one of the applicable standards was not exceeded and there is insufficient information to determine whether the other is being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9440, Turbidity	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8841

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2004. (No samples were collected in 2002.) Turbidity in two of five samples was below the detection level. The remaining samples ranged from 2.1 to 3.2 NTU. The MCL was not exceeded.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for turbidity is 5 NTU.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Five turbidity measurements expressed as NTU were taken between 2001 and 2004. No measurements were taken in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9440, Turbidity	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8840

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Lahontan Basin Plan's regionwide turbidity objective states:

"Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Five turbidity measurements expressed as NTU were taken between 2001 and 2004. No measurements were taken in 2002.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9440, Turbidity	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8842

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey measured turbidity as NTRU quarterly under the Region 6 SWAMP program between 2004 and 2005. All four samples were below the detection level.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Four quarterly turbidity measurements expressed as NTRU were taken in 2004 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9440, Turbidity	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8843

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey measured turbidity as NTRU quarterly under the Region 6 SWAMP program between 2004 and 2005. All four samples were below the detection level.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The drinking water Maximum Contaminant Level is expressed as NTU. There are no standards or criteria for turbidity as NTRU for the protection of human health.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Four quarterly turbidity measurements expressed as NTRU were taken in 2004 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9347	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. There are no applicable standards or criteria for dissolved vanadium. None of the total vanadium samples exceeds the applicable criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 10 samples for total vanadium exceeded the California Notification Level criterion and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9347, Vanadium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7229

Pollutant:

Vanadium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved vanadium in 2 of 10 samples were below the detection level. Vanadium concentrations in the remaining 8 samples ranged from 0.3 to 0.9 ug/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 9347, Vanadium	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7230

Pollutant:

Vanadium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of total vanadium in 5 of 10 samples were below the detection level. The presence of vanadium in the remaining 5 samples was verified but not quantified. The criterion was not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Drinking Water Notification and Response Levels: An Overview

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):


DECISION ID	9356	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable water quality standard(s). 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 10 dissolved zinc samples exceeded the California Toxics Rule standards. None of 10 total zinc 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9356, Zinc	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7232

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. Of ten samples for total recoverable zinc, one was below the detection level and four were estimated values. Concentrations of total recoverable zinc in the remaining 4 samples ranged from 3 to 4 ug/L. The MCL was not violated.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for zinc is 5 mg/L, equivalent to 5000 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):

Line of Evidence (LOE) for Decision ID 9356, Zinc	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7231

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. One of 10 samples for dissolved zinc was below the detection level, and 2 were estimated values. Concentrations of dissolved zinc in the remaining samples ranged from 0.6 to 2.8 ug/L. The CTR standards were not violated.
Concentrations of dissolved zinc in 12 samples ranged from 0.8 to 3 ug/L Three samples were estimated values and two were below detection levels The standards were not violated..

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Toxics Rule (CTR) freshwater aquatic life standards for zinc are dependent on hardness. At the hardness levels reported for this station, the acute toxicity standard ranges from 31.37 to 89.16 ug/L, and the chronic toxicity standard ranges from 31.63 to 89.89 ug/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9441	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

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

Regional Board Conclusion:	The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the data are insufficient to establish baseline and trend conditions under the requirements of Listing Policy section 3.10.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

USEPA Action (if applicable):

Line of Evidence (LOE) for Decision ID 9441, pH	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

8839

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station approximately quarterly under the Region 6 SWAMP program between 2001 and 2005. (No samples were collected in 2002.) The range of pH in 8 field measurements was 7.5 to 8.4 units. An additional two laboratory measurements were 8 and 7.8 units. There are insufficient data to document natural background conditions or to detect trends.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The regionwide water quality objective for pH in the Lahontan Basin Plan states:

"In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units.

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

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Eight field pH measurements were taken approximately quarterly between August 2001 and July 2005. No measurements were taken in 2002. An additional two laboratory measurements were taken in August and November 2001.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):


DECISION ID	9352	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

Pollutant:	Manganese
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	Natural Sources
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. There are no applicable standards or criteria for dissolved manganese. Eight of the total manganese 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 expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Eight of 10 total manganese 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. State Board Review and Conclusion: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for manganese based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. The State Water Board recommendation is based on the following: Lahontan Regional Board staff had decided not to list this water body because staff thought it had insufficient information to make a decision to list. However, State Board staff finds there are 10 samples to make a decision and this meets the sample size requirements of Table 3.1 of the Listing Policy. State Water Board staff re-evaluated the available data and the recommendation has been revised. On August 4, 2010 the State Water Board approved the staff recommendation to place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is: Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Eight of 10 total manganese 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.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because, although one of the applicable water quality standards is being exceeded, the data are not temporally representative.

State Board Review of Regional Board Conclusion and Recommendation:

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

USEPA Action (if applicable):	USEPA approved the listing of this water body as a water quality limited segment requiring a TMDL for this pollutant.

Line of Evidence (LOE) for Decision ID 9352, Manganese	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7220

Pollutant:

Manganese

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Concentrations of total manganese ranged from 34 to 157 ug/L. Eight samples exceeded the MCL.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for manganese is 50 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten 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):

Line of Evidence (LOE) for Decision ID 9352, Manganese	Region 6
Mammoth Creek (Twin Lakes outlet to Old Mammoth Road)

LOE ID:

7219

Pollutant:

Manganese

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Fixed station physical/chemical (conventional plus toxic pollutants)

Data Used to Assess Water Quality:

The U.S. Geological Survey sampled this station under the Region 6 SWAMP program approximately quarterly between 2001 and 2005. Concentrations of dissolved manganese in 10 samples ranged from 13.7 to 157 ug/L.

Data Reference:

2007. SWAMP Data for the Owens Hydrologic Unit

SWAMP Data:

SWAMP

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:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

One station, "Mammoth Creek at Old Mammoth Road" was sampled.

Temporal Representation:

Ten samples were collected approximately quarterly between 2001 and 2005.

Environmental Conditions:

QAPP Information:

The data meet the quality assurance requirements of the SWAMP QAPP.

QAPP Information Reference(s):