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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Hilton Creek
Water Body ID: CAR6031008020070824170247
Water Body Type: River & Stream
 
DECISION ID
7812
 
Pollutant: Chloride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples or annual average datapoints 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 satisfiy 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 15 individual samples or 5 annual average datapoints exceeded the applicable water quality objectives and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7812
 
LOE ID: 5671
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Of 15 chloride samples, 10 were estimates or below the detection level. Chloride concentrations in the remaining 5 samples ranged from 0.2 to 0.75 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
  2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chloride is 250 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Fifteen quarterly samples were collected between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

 
LOE ID: 5659
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Of 15 chloride samples, 10 were estimates or below the detection level. Chloride concentrations in the remaining 5 samples ranged from 0.2 to 0.75 mg/L.. The site-specific objective was not exceeded.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The site-specific objective (from Lahontan Basin Plan Table 3-17) includes an annual average of 0.8 mg/L and a 90th percentile value of 2.0 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Fifteen quarterly samples were collected between 2001 and 2005. Sampling frequency was inadequate for calculation of representative annual averages.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7778
 
Pollutant: Dissolved oxygen saturation
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples 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.
3. None of four samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7778
 
LOE ID: 6082
 
Pollutant: Dissolved oxygen saturation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: OThe U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program. Percent saturation of dissolved oxygen in four samples collected between October 2004 and July 2005 ranged from 94 to 108 percent. The objective was not exceeded.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide narrative objective for dissolved oxygen provides that percent saturation shall not be depressed more than 10 percent nor shall the minimum dissolved oxygen concentration be less than 80 percent of saturation.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Crowley Lake, was sampled.
Temporal Representation: Four quarterly measurements of dissolved oxygen saturation were taken between October 2004 and July 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7697
 
Pollutant: Fecal Coliform
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

Two of evidence are available in the administrative record to assess this pollutant. One of the samples exceeds the water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. One of five samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7697
 
LOE ID: 5705
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 5
Number of Exceedances: 1
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program. Four of 5 fecal coliform samples collected between July 2004 and July 2005 were estimates or below the detection level. The remaining sample was 100 colonies per 100 milliliters, exceeding the limits in the water quality objective.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected as evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected." .
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Five samples were collected at quarterly intervals between July 2004 and July 2005
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

 
LOE ID: 5704
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 5
Number of Exceedances: 1
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program. Four of 5 fecal coliform samples collected between July 2004 and July 2005 were estimates or below the detection level. The remaining sample was 100 colonies per 100 milliliters, exceeding the limits in the water quality objective.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock wastes. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected as evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected." .
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Five samples were collected at quarterly intervals between July 2004 and July 2005
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10410
 
Pollutant: Nitrate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). None of the annual average datapoints exceeds the site-specific water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 16 samples exceeded the MCL. None of 5 annual average datapoints exceeded the site-specific objective. (Only two numerical averages could be calculated due to estimated and below detection level sample values.) this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10410
 
LOE ID: 21409
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Sixteen samples each were collected for nitrite and nitrite plus nitrate. Eight of 16 calculated nitrate concentrations were below the detection level. The remainder ranged from 0 to 0.53 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
  2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate (expressed "as nitrate") is 45 mg/L, equivalent to 10 mg/L expressed "as N."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Sixteen quarterly samples each were collected for nitrite and for nitrite plus nitrate between 2001 and 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

 
LOE ID: 21407
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program between 2001 and 2005. Sixteen quarterly samples each were collected for nitrite and for nitrite plus nitrate. Because of estimated and below detection level values in the constituents, numerical annual average concentrations of nitrate could not be calculated for 2001, 2002, and 2003. The annual average concentrations for 2004 and 2005 were 0.059 and 0.126 mg/L. The objective was not violated.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The site-specific objective (from Lahontan Basin Plan Table 3-17) includes an annual average nitrate (as nitrate) concentration of 0.3 mg/L and a 90th percentile value of 0.5 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Crowley Lake, was sampled.
Temporal Representation: Sixteen quarterly samples each were collected for nitrite and for nitrite plus nitrate between 2001 and 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10411
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum.Contaminant Level (MCL).

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 16 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10411
 
LOE ID: 21404
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Concentrations of nitrite plus nitrate in 5 of 16 samples were below the detection level. Another two samples were estimated values. Concentrations in the remaining samples ranged from 0.001 to 0.054 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite plus nitrate is 10 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Sixteen quarterly samples were collected between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10413
 
Pollutant: Nitrite
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL).

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 16 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10413
 
LOE ID: 21403
 
Pollutant: Nitrite
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Concentrations of nitrite in 8 of 16 samples were below the detection level. Concentrations in the remaining samples ranged from 0.001 to 0.002 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite is 1 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Sixteen quarterly samples were collected between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
16116
 
Pollutant: Oxygen, Dissolved
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Six of the samples exceed the water quality objective. Although these exceedences could require listing under the Listing Policy's binomial model, listing is not recommended because quarterly samples do not capture the diel, seasonal and annual variation expected in dissolved xoygen concentrations.

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. Six of 15 samples exceeded the 1-day minimum water quality objective and exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. However, lsiting is not recommended because quartelry samples are not temporally representative of the expected variation in dissolved oxygen concentrations.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 16116
 
LOE ID: 5819
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 6
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Dissolved oxygen concentrations ranged from 6.5 to 11.8 mg/L. Six of fifteen quarterly samples were below the 1-day minimum limit.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The water quality objective for or waters designated for the COLD and SPWN beneficial uses is a 1-day minimum of 8 mg/L (Lahontan Basin Plan Table 3-6).
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Crowley Lake, was sampled.
Temporal Representation: Fifteen measurements of dissolved oxygen were collected between August 2001 and July 2006.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10414
 
Pollutant: Phosphate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the annual average datapoints exceeds the site-specific water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 4 annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10414
 
LOE ID: 21408
 
Pollutant: Phosphate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program between 2002 and 2005. Six of fourteen samples for PO4 as P were below the detection level. Concentrations in the remaining samples ranged from 0.001 to 0.017 mg/L. Fourteen calculated concentrations of P04 included 6 below detection level values; the remainder ranged from 0.003 to 0.052 mg/L. of . Because of the below detection level values, the annual average concentrations for 2002 and 2003 could not be calculated. The annual average concentrations for 2004 and 2005 were 0.015 and 0.001 mg/L. The objective was not violated.

An additional sample for hydrolyzable P plus PO4 was collected on November 27, 2001. The concentration was 0.08 mg/L.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The site-specific objective (from Lahontan Basin Plan Table 3-17) includes an annual average dissolved orthophosphate concentration of 0.03 mg/L and a 90th percentile value of 0.05 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Crowley Lake, was sampled.
Temporal Representation: Fourteen quarterly samples for PO4 as P were collected between 2002 and 2005. One sample for hydrolyzable P plus PO4 was collected on November 27, 2001.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10418
 
Pollutant: Phosphorus
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. No biological data are available for assessment whether any of the chemical samples exceeds the water quality objective for biostimulatory substances.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. No biological data are available for assessment of compliance with the objective for biostimulatory substances and the 12 total phosphorus samples cannot be assessed usin Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because no biological data are available for assessment of compliance with the applicable water quality objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10418
 
LOE ID: 21412
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 12
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program between 2002 and 2005. Concentrations of total phosphorus in 12 quarterly samples ranged from 0.004 to 0.034 mg/L.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include a site-specific objective (SSO) for total phosphorus in Hilton Creek. The narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Crowley Lake, was sampled.
Temporal Representation: Twelve quarterly samples were collected between 2002 and 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7787
 
Pollutant: Sediment
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: The Lahontan Basin Plan's narrative water quality objective is an antidegradation based objective that provides that there shall be no increases in suspended sediment concentrations or loads. This pollutant is being considered for placement on the section 303(d) list under section 3.10 of the Listing Policy, which deals with trends in water quality.

One line of evidence, based on quarterly sampling, is available in the administrative record to assess this pollutant. It includes 16 suspended sediment concentration values and 8 suspended sediment load values calculated from instantaneous discharge measurements.

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

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy Section 3.10.
3. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the requirements of Listing Policy section 3.10 are not met.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7787
 
LOE ID: 5674
 
Pollutant: Sediment
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Suspended sediment concentrations in 16 samples ranged from 18 to 63 mg/L. Instantaneous discharges measured concurrenty ranged from 1.2 to 33 cubic feet per second. Calculated suspended sediment loads (for 8 samples) ranged from 0.01 to 0.89 tons per day.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The objective from the Lahontan Basin Plan states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Sixteen quarterly suspended sediment samples were collected between 2001 and 2005. Eight suspended sediment load calculations were done for suspended sediment and flow data collected between 2003 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7605
 
Pollutant: Specific Conductance
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

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

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. None of 17 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7605
 
LOE ID: 5673
 
Pollutant: Specific Conductance
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Specific conductance in 15 field measurements ranged from 22 to 54 uS/cm. Two additional laboratory measurements from samples collected on the same dates as field measurements were 32 and 38 uS/cm. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, HIlton Creek at Lake Crowley, was sampled.
Temporal Representation: Fifteen quarterly field measurements and two laboratory measurements were taken between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7698
 
Pollutant: Temperature, water
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: The Lahontan Basin Plan's narrative temperature objective is an antidegradation-based objective that requires that there be no change in temperature in waters designated for the Cold Freshwater Habitat (COLD) beneficial use. The objective does not include specific numerical limits for protection of the COLD use. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects.

One line of evidence is available to support this decision. There are not enough temperature samples to establish baseline conditions (including diel, seasonal, annual and interannual variations in temperature) or to detect declining trends in the temperature regime if such trends exist.

Because temperature samples were collected only quarterly, weekly and monthly average data are not available for comparison with guidelines in the scientific literature for the temperature requirements of sensitive aquatic species such as salmonids, as directed in Listing Policy Section 6.1.5.9.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because available data are insufficient for assessment under Listing Policy Sections 3.10 and 6.1.5.9.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7698
 
LOE ID: 5677
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. Temperatures in 16 quarterly measurements taken ranged from 0 to 21 degrees Celsius.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The applicable language from the Lahontan Basin Plan's objective for temperature states: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction fo the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses.

For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered.

Temperature objectives for COLD interstate waters and WARM interstate waters are as specified in the ‘Water Quality Control Plan for Control of Temperature in The Coastal and Interstate Waters and Encosed Bays and Estuaries of California’ including any revisions."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowly, was sampled.
Temporal Representation: Sixteen quarterly measurements of water temperature were taken between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
7811
 
Pollutant: Total Dissolved Solids
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of 16 individual samples exceed the Maximum Contaminant Level. Two of 5 annual averages (calculated based on 2 to 4 samples per year) exceeded 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 16 individual samples exceeded the Maximum Contaminant Level. Two of five annual averages exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 7811
 
LOE ID: 5675
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 2
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. TDS concentrations in 16 samples ranged from 18 to 63 mg/L. Annual average concentrations ranged from 20 to 37 mg/L. The annual average objective was exceeded in 2 of 5 years.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The site-pecific objective for Total Dissolved Solids (TDS) in Lahontan Basin Plan Table 3-17, includes an annual average of 28 mg/L and a 90th percentile value of 34 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Sixteen quarterly samples were collected between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

 
LOE ID: 5676
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. TDS concentrations in 16 samples ranged from 18 to 63 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for Total Dissolved Solids (TDS) is 500 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Sixteen quarterly samples were collected between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10421
 
Pollutant: Total Kjeldahl Nitrogen (TKN)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. No biological data are available for assessment whether of the chemical samples exceeds the water quality objective for biostimulatory substances.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. No biological data are available for assessment of compliance with the objective for biostimulatory substances. The chemical data cannot be assessed using Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because no biological data are available for assessment of compliance with the applicable water quality objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10421
 
LOE ID: 21405
 
Pollutant: Total Kjeldahl Nitrogen (TKN)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 16
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program between 2001 and 2005. One of 16 quarterly samples for TKN was an estimated value. Concentrations of TKN in the other samples ranged from 0.03 to 0.32 mg/L.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include a site-specific objective (SSO) for total Kjeldahl nitrogen (TKN) in Hilton Creek. The narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Crowley Lake, was sampled.
Temporal Representation: Sixteen quarterly samples were collected between 2001 and 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10415
 
Pollutant: Total Nitrogen as N
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. None of the annual average datapoints exceeds the site-specific water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 5 annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10415
 
LOE ID: 21406
 
Pollutant: Total Nitrogen as N
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek under the Region 6 SWAMP program between 2001 and 2005. Sixteen quarterly samples each were collected for total Kjeldahl nitrogen and nitrite plus nitrate. Because of estimated and below detection level values in the constituents, the annual average concentrations of total nitrogen for 2001, 2002, and 2003 were estimates. The annual average concentrations for 2004 and 2005 were 0.207 and 0.160 mg/L. The objective was not violated.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The site-specific objective (from Lahontan Basin Plan Table 3-17) includes an annual average total nitrogen concentration of 0.5 mg/L and a 90th percentile value of 0.6 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Crowley Lake, was sampled.
Temporal Representation: Sixteen quarterly samples each were collected for total Kjeldahl nitrogen and nitrite plus nitrate between 2001 and 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10416
 
Pollutant: Turbidity
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Four lines of evidence are available in the administrative record to assess this pollutant. Separate lines of evidence were prepared for data expressed as NTU and NTRU. The two types of units are measured differently and are not directly comparable. There are no specific state or federal standards or criteria for turbidity expressed as NTRU.

None of the samples expressed as NTU exceeds the Maximum Contaminant level. The Lahontan Basin Plan's narrative turbidity objective is a non-degradation objective, and sample numbers are insufficient to establish baseline conditions or detect trends as required under Listing Policy Section 3.10.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and turbidity values in streams of the Lahontan Region.
3. None of 11 samples expressed as NTU exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. It is not possible to determine whether the narrative turbidity objective was exceeded because the requirements of Listing Policy Section 3.10 were not met.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because one of the applicable water quality standards is not being exceeded and there is insufficient information to determine compliance with the other standard..
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10416
 
LOE ID: 21410
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured turbidity as NTRU at Hilton Creek between 2004 and 2005 under the Region 6 SWAMP program. Three of four turbidity measurements reported as NTRU were below detection levels; the remaining sample was 27 NTRU.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The regionwide turbidity objective in the Lahontan Basin Plan states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Four quarterly turbidity measurements expressed as NTRU were taken in 2004 and 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

 
LOE ID: 5678
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured turbidity as NTU at Hilton Creek between 2001 and 2004 under the Region 6 SWAMP program. . Eleven turbidity measurements recorded as NTU ranged from <2.0 to 5 NTU. Four of these samples were estimated or below detection level values.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The regionwide turbidity objective in the Lahontan Basin Plan states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Eleven quarterly turbidity measurements expressed as NTU were collected between 2001 and 2004
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

 
LOE ID: 21411
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 4
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured turbidity as NTRU at Hilton Creek between 2004 and 2005 under the Region 6 SWAMP program. Three of four turbidity measurements reported as NTRU were below detection levels; the remaining sample was 27 NTRU.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: There are no state or federal water quality standards or criteria for turbidity expressed as NTRU. The California Maximum Contaminant Level (MCL) for turbidity is 5 NTU.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Four quarterly turbidity measurements reported as NTRU were taken in 2004 and 2005..
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

 
LOE ID: 5679
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 11
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey measured turbidity as NTU at Hilton Creek between 2001 and 2004 under the Region 6 SWAMP program. . Eleven turbidity measurements recorded as NTU ranged from <2.0 to 5 NTU. Four of these samples were estimated or below detection level values. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for turbidity is 5 NTU.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Eleven quarterly turbidity measurements expressed as NTU were taken between 2001 and 2004.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
10422
 
Pollutant: pH
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects.

One line of available to support this decision. There are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the data are insufficient to document baseline and trend conditions as required by section 3.10 of the listing policy.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 10422
 
LOE ID: 5672
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled Hilton Creek between 2001 and 2005 under the Region 6 SWAMP program. The pH values in 14 field measurements ranged from 7.1 to 7.9 units.
Data Reference: 2007. SWAMP Data for the Owens Hydrologic Unit
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH states: " In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units.

The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Hilton Creek at Lake Crowley, was sampled.
Temporal Representation: Fourteen quarterly pH measurements were collected between 2001 and 2005.
Environmental Conditions: Hilton Creek is a tributary of Crowley Lake, a reservoir on the Owens River. The creek’s headwaters are near the Sierra Nevada crest. Section 319-funded watershed restoration work to address livestock grazing problems has been completed. In addition to the Cold Freshwater Habitat beneficial use, Hilton Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):