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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Slate Creek
Water Body ID: CAR6380001220080811160901
Water Body Type: River & Stream
 
DECISION ID
14122
 
Pollutant: Fecal Coliform
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.

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

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

This conclusion is based on the staff findings that:
1. The data used do not 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 or Table 3.2 of the Policy.
3. One of two 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 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 14122
 
LOE ID: 25943
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Fecal coliform counts in two samples were 2 and 36 colonies per 100 mL. (Because the objective requires a minimum of five samples in a 30-day period, log means were not calculated.)
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
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 waste.

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 a 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: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
LOE ID: 25944
 
Pollutant: Fecal Coliform
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Fecal coliform counts in two samples were 2 and 36 colonies per 100 mL. (Because the objective requires a minimum of five samples in a 30-day period, a log mean was not calculated.)
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
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 waste.

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 a 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: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
DECISION ID
15259
 
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. Neither of two samples exceeds the Maximum Contaminant Level (MCL). No biological data are available for assessment of compliance with the water quality objective for biostimulatory substances..

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

This conclusion is based on the staff findings that:
1. The data used do not 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. Neither of two samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. No data are available for assessment of compliance with the water quality objective for biostimulatory substances.
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 15259
 
LOE ID: 25938
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two samples had NO3-N concentrations of 0.07 and 0.12 mg/L.The MCL was not exceeded.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L expressed "as nitrate," equivalent to 10 mg/L expressed "as N."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
LOE ID: 25939
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two samples had NO3-N concentrations of 0.07 and 0.12 mg/L.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include site specific objectives for this water body. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
DECISION ID
15257
 
Pollutant: Phosphate
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. No biological data are available to assess whether either of the two 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.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. No biological data are available for assessment of compliance with the objective..
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 15257
 
LOE ID: 25940
 
Pollutant: Phosphate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two samples had PO4-P concentrations of 0.28 and 0.3 mg/L.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include site specific objectives for this water body. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
DECISION ID
15260
 
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: One line of evidence is available in the administrative record to assess this pollutant. The water quality objective for sediment is antidegradation based. The two available samples cannot be used to document baseline and trend conditions to assess compliance with the objective using 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 do not satisfy the data quality requirements of section 6.1.4 of the Policy (both samples were collected within one month..
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. The two available samples are insufficient to assess compliance with the objective under section 3.10 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 15260
 
LOE ID: 25945
 
Pollutant: Sediment
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two samples had suspended sediment concentrations of 0.78 and 2.5 mg/L.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's narrative objective states:
"The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
DECISION ID
15258
 
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. Neither of two 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.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 or Table 3.2 of the Policy.
3. Neither of two 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 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 15258
 
LOE ID: 25935
 
Pollutant: Specific Conductance
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two specific conductance measurements were 148 and 181 uS/cm. The MCL was not exceeded.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
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: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
DECISION ID
15261
 
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: One line of evidence is available in the administrative record to assess this pollutant. The Lahontan Basin Plan's temperature objective is antidegradation-based and the available data are insufficient to document baseline and trend conditions as required by section 3.10 of the Listing Policy.

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.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. The two available samples are insufficient to determine compliance with the objective under seciton 3.10 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 15261
 
LOE ID: 25937
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two water temperature measurements were both 20 degrees Celsius.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
Water Quality Objective/Criterion: The relevant sections of the Lahontan Basin Plan's temperature objective are as follows: "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."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
DECISION ID
15262
 
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: Two lines of evidence are available in the administrative record to assess this pollutant. Two of the samples exceed the Maximum Contaminant Level (MCL).

The narrative water quality objective for turbidity is an antidegradation-based objective and the three available samples are insufficient to document baseline and trend conditions 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 do not 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. Two of two samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.(The minimum sample number requirements of Table 3.2 are not met.)
4. The requirements of Listing Policy section 3.10 to document baseline and trend conditions are not met in relation to the narrative water quality objective.
5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because 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 15262
 
LOE ID: 25941
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two samples had turbidities of 12.8 and 7.58 units.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
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: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
LOE ID: 25942
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
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. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two samples had turbidities of 12.8 and 7.58 units. Both samples exceeded the MCL.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
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: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):
 
DECISION ID
15263
 
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: One line of evidence is available in the administrative record to assess this pollutant. The water quality objective for pH is antidegradation based and the available data are insufficient to document baseline and trend conditions as required by section 3.10 of the Listing Policy.

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.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. The two available samples cannot be used to document baseline and trend conditions under the requirements of Listing Policy section 3.10.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because 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 15263
 
LOE ID: 25936
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Bureau of Land Management sampled two stations on Slate Creek on July 25, 2002. Two pH measurements were 9.2 and 9.64 units.
Data Reference: Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties.
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's objective for pH states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units.

The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two stations, Slate Creek below Heath Dam, and Slate Creek above Horse Camp Spring Creek, were sampled.
Temporal Representation: Two samples were collected on July 25, 2002.
Environmental Conditions: Slate Creek flows into Grasshopper Valley, northeast of Eagle Lake in Lassen County. As a minor surface water of the Madeline Plains Hydrologic Unit (HU No. 638.00) it has categorically designated beneficial uses. No site-specific water quality objectives apply
QAPP Information: No quality assurance information was submitted with the data.
QAPP Information Reference(s):