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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Mojave River (Upper Narrows to Lower Narrows)
Water Body ID: CAR6282000020080817142158
Water Body Type: River & Stream
 
DECISION ID
8047
 
Pollutant: 1, 1, 2-trichloro-1, 2, 2-trifluoroethane | 1, 1-dichloroethane | 1, 3 -dichlorobenzene | 1, 4 -dichlorobenzene | 1,1,1-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinyldine Chloride | 1,2-Dichloroethane | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Chlorobenzene (mono) | Chlorodibromomethane | Chloroform | Dichlorobromomethane | Dichlorodifluoromethane | Dichloromethane | Diethyl ether | Diisopropyl ether | Ethylbenzene | Methyl tert-pentyl ether | Styrene | Tert-butyl ethyl ether | Tetrachloroethylene/PCE | Toluene | Trichloroethene | Trichlorofluoromethane (CFC-11) | Vinyl chloride | cis-1,2-Dichloroethylene | m-Xylene | o-Dichlorobenzene | o-Xylene
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: These pollutants are being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy.
3. All of the samples analyzed for each of 32 pollutants were below detection levels. Per section 6.1.5.5 of the Listing Policy, the applicable standards are presumed to be attained.
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 8047
 
LOE ID: 6806
 
Pollutant: 1, 1, 2-trichloro-1, 2, 2-trifluoroethane | 1, 1-dichloroethane | 1, 3 -dichlorobenzene | 1, 4 -dichlorobenzene | 1,1,1-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinyldine Chloride | 1,2-Dichloroethane | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Chlorobenzene (mono) | Chlorodibromomethane | Chloroform | Dichlorobromomethane | Dichlorodifluoromethane | Dichloromethane | Diethyl ether | Diisopropyl ether | Ethylbenzene | Methyl tert-pentyl ether | Styrene | Tert-butyl ethyl ether | Tetrachloroethylene/PCE | Toluene | Trichloroethene | Trichlorofluoromethane (CFC-11) | Vinyl chloride | cis-1,2-Dichloroethylene | m-Xylene | o-Dichlorobenzene
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Fifteen quarterly samples were analyzed for each of 32 organic compounds. All of these samples were below detection levels. Per Listing Policy Section 6.1.5.5., none of the applicable standards were exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The following listed organic compounds have no state or federal freshwater aquatic life standards or criteria: 1, 1, 2 trichloro, 1, 2, 2 trifluoroethane, diethyl ether, diisopropyl ether, methyl tert pentyl ether, styrene, tert butyl ethyl ether, vinyl chloride, m xylene, and o xylene. The U.S. Environmental Protection Agency (USEPA) Lowest Observed Effect Level (LOEL) criteria for other listed compounds are as follows. (Single numbers (or the first of two numbers) are the acute toxicity criteria; the second of two numbers is the chronic toxicity criterion.) 1, 1, dichloroethane, 1120 ug/L/ 763 ug/L; 1, 3 dichlorobenzene, 11,800 ug/L/ 20,000 ug/L; 1, 4 dichlorobenzene, 1120 ug/L/ 763 ug/L; 1, 1, 1 trichloroethane. 18,000 ug/L; 1, 2 dichloroethylene, 11, 600 ug/L; 1, 2 dichloroethane 11, 800 ug/L/ 20, 000 ug/L; 1, 2 dichloroethylene (trans), 11,600 ug/L; 1, 2 dichloropropane, 23,000 ug/L/ 5700 ug/L; benzene, 5300 ug/L; bromoform, 11,000 ug/L; carbon tetrachloride, 35,200 ug/L, chlorobenzene, 250 ug/L; chloroform 28,900 ug/L/ 1240 ug/L; chlorodibromomethane, 11,000 ug/L; dichlorobromomethane, 11,000 ug/L; dichloromethane, 11,000 ug/L; ethylbenzene, 32,000 ug/L; tetrachloroethylene, 5280 ug/L/840 ug/L; toluene, 17,500 ug/L; trihloroethene, 45,000 ug/L; trichlorofluoromethane, 11,000 ug/L; cis,1, 2 dichloroethylene, 11, 600 ug/L, and o-dichlorobenzene, 1120 ug/L/763 ug/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
  Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River below [Mojave] Forks Reservoir, was sampled.
Temporal Representation: Fifteen quarterly samples were analyzed for each of 32 organic compounds.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations. The Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6807
 
Pollutant: 1, 1, 2-trichloro-1, 2, 2-trifluoroethane | 1, 1-dichloroethane | 1, 3 -dichlorobenzene | 1, 4 -dichlorobenzene | 1,1,1-Trichloroethane | 1,1-Dichloroethylene (DCE)/ Vinyldine Chloride | 1,2-Dichloroethane | 1,2-Dichloroethylene,-trans | 1,2-Dichloropropane | Benzene | Bromoform | Carbon tetrachloride | Chlorobenzene (mono) | Chlorodibromomethane | Dichlorobromomethane | Dichlorodifluoromethane | Dichloromethane | Diethyl ether | Diisopropyl ether | Ethylbenzene | Methyl tert-pentyl ether | Styrene | Tert-butyl ethyl ether | Tetrachloroethylene/PCE | Toluene | Trichloroethene | Trichlorofluoromethane (CFC-11) | Vinyl chloride | cis-1,2-Dichloroethylene | m-Xylene | o-Dichlorobenzene | o-Xylene
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 this station under the Region 6 SWAMP program between 2001 and 2005. Fifteen quarterly samples were analyzed for each of 32 organic compounds. All of these samples were below detection levels. Per Listing Policy Section 6.1.5.5., none of the applicable standards were exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: There are no applicable state or federal human health standards or criteria for the following listed chemicals: diethyl ether, diisopropyl ether, methyl tert pentyl ether, and tert butyl ethyl ether. The California Sstate Notification Level for dichlorodifluoromethane is 1000 ug/L. The California Maximum Contaminant Levels for the remaining listed organic compounds are as follows: 1, 1, 2 trichloro 1, 2, 2 trifluoroethane, 1200 ug/L; 1, 1 dichloroethane, 0.5 ug/L; 1, 3 dichlorobenzene, 600 ug/L; 1, 4 dichlorobenzene, 5 ug/L; 1, 1,1 trichloroethane, 200 ug/L; 1 2 dichloroethylene, 6 ug/L; 1, 2 dichloroethane, 0.5 ug/L; 1, 2 dichloroethylene (trans), 10 ug/L; 1, 2 dichloropropane, 5 ug/L; benzene, bromoform, 80 ug/L; chloroform, 80 ug/L; carbon tetrachloride, 0.5 ug/L; chlorobenzene (mono) 70 ug/L; chlorodibromomethane, 80 ug/L; dichlorobromomethane, 80 ug/L; dichloromethane, 5 ug/L; ethylbenzene, 300 ug/L; styrene, 100 ug/L; tetrochloroethylene, 5 ug/L; toluene, 150 ug/L; trichloroethene, 5 ug/L, trichlorofluoromethane, 150 ug/L; vinyl chloride, 0.5 ug/L, cis 1, 2 dichloroethylene, 6 ug/L; m-xylene, 1750 ug/L; o-dichlorobenzene, 600 ug/L; o-xylene, 1750 ug/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River below [Mojave] Forks Reservoir, was sampled.
Temporal Representation: Fifteen quarterly samples were analyzed for each of 32 organic compounds.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.The Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9100
 
Pollutant: Boron
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the applicable water quality objectives.

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 samples exceeded the California State Notification Level criterion. 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 9100
 
LOE ID: 8417
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 14
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Boron concentrations in 14 samples ranged from 72 to 275 ug/L. The criterion was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The California State Notification Level criterion is 1000 ug/L.
Objective/Criterion Reference: Compilation of Water Quality Goals
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fourteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 8415
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Boron concentrations in 14 samples ranged from 72 to 275 ug/L. Annual average concentrations (based on 2 to 4 samples per year) ranged from 126 to 168 ug/L.The annual average objective was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The site-specific objective for the Mojave River at Upper Narrows station (Lahontan Basin Plan Table 3-21, Station 19) includes an annual average boron concentration of 0.2 mg/L (200 ug/L) and a 90th percentile value of 0.3 mg/L (300 ug/L).
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fourteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8072
 
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 exceed the applicable water quality objectives.

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 15 individual samples exceeded the MCL. None 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 8072
 
LOE ID: 6862
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Chloride concentrations in 15 samples ranged from 20.3 to 72.3 mg/L. The annual average objective was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The site-specific objective for the Mojave River at Upper Narrows station (Lahontan Basin Plan Table 3-21) includes and annual average chloride concentration of 75 mg/L and a 90th percentile value of 100 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6863
 
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 this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Chloride concentrations in 15 samples ranged from 20.3 to 72.3 mg/L. The MCL was not exceeded.
Data Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
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, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8082
 
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. Four of the samples exceed the water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. Four of six samples exceeded the water quality objective for percent saturation 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 8082
 
LOE ID: 6871
 
Pollutant: Dissolved oxygen saturation
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 4
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2003 to 2005 under the Region 6 SWAMP program. Percent saturation in 6 quarterly measurements ranged from 30 to 102 percent; 4 of the 6 measurements were below 80 percent.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The narrative objective in the Lahontan Basin Plan requires that percent saturation shall not be depressed by more than 10 percent and minimum dissolved oxygen concentration shall not be less than 80 percent saturation.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Six measurements of percent saturation of dissolved oxygen were taken approximately quarterly between 2003 and 2005 (one measurement in October 2003 and 5 between April 2004 and July 2005).
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9101
 
Pollutant: Fluoride
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Five annual average datapoints, (based on only 2 to 4 samples per year) exceed the site-specific water quality objective. However, listing is not recommended because the samples are not temporally representative.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 14 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five of 5 annual average datapoints exceeded the site-specific objective and this exceeds the allowable frequency listed in Table 3.2.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because, although one of the applicable standards is being exceeded, the data are not temporally representative.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9101
 
LOE ID: 6864
 
Pollutant: Fluoride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 14
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Chloride concentrations in 14 samples ranged from 0.3 to 0.6 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for fluoride is 2 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fourteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6865
 
Pollutant: Fluoride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 5
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 (2 to 4 samples per year) under the Region 6 SWAMP program. Fluoride concentrations in 14 quarterly samples ranged from 0.3 to 0.6 mg/L. Annual average concentrations ranged from 0.35 to 0.50 mg/L.The annual average objective was exceeded in five out of five years.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The site-specific objective from Basin Plan Table 3-21 (for Station 19) includes an annual average fluoride concentration of 0.2 mg/L and a 90th percentile value of 0 1.5 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fourteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations. Fluoride at this station probably comes from natural geothermal sources.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8048
 
Pollutant: Methyl Tertiary-Butyl Ether (MTBE)
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 Califonria Maximum Contaminant Level or the USEPA aquatic life criterion.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 15 samples exceeded either of the applicable standards 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 8048
 
LOE ID: 25253
 
Pollutant: Methyl Tertiary-Butyl Ether (MTBE)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled MTBE at this station under the Region 6 SWAMP program. Of 15 quarterly samples, 8 were below the detection level and 5 were estimated values. MTBE concentrations in the remaining two samples were 0.2 and 0.3 ug/L. The criteria were not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The U.S. Environmental Protection Agency's national freshwater aquatic life criteria for methyl tert butyl ether (MTBE) are an acute value of 151, 000 ug/L and a chronic value of 51,000 ug/L.
Objective/Criterion Reference: National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6808
 
Pollutant: Methyl Tertiary-Butyl Ether (MTBE)
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 MTBE at this station under the Region 6 SWAMP program. Of 15 quarterly samples, 8 were below the detection level and 5 were estimated values. MTBE concentrations in the remaining two samples were 0.2 and 0.3 ug/L. The MCLs were not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The primary MCL for MTBE is 0.013 mg/L (13 ug/L). The secondary MCL is 0.005 mg/L (5 ug/L).
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8086
 
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 exceed the water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 15 samples exceeded the applicable water quality objectives 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 8086
 
LOE ID: 6880
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Nitrate "as N" was calculated from available data for nitrate and "nitrate plus nitrite". Calculated nitrate concentrations in 15 samples ranged from an estimated 0.2 to 1.103 mg/L expressed "as N." Expressed "as nitrate" the maximum value is 4.96 mg/L. The objective was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The objective for the West Fork Mojave River (at Lower Narrows) in Lahontan Basin Plan Table 3-20 applies upstream through the Tributary Rule. This objective is a maximum of 6 mg/L nitrate "as nitrate."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected for nitrite and for nitrate plus nitrite between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6879
 
Pollutant: Nitrate
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 this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Nitrate was calculated from available data for nitrate and "nitrate plus nitrite". Calculated nitrate concentrations in 15 samples ranged from 0.2 to 1.103 mg/L, expressed "as N." The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L expressed "as nitrate", equivalent to 10 mg/L expressed "as N.".
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected for nitrite and for nitrate plus nitrite between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8089
 
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.

Two of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the California Maximum Contaminant Level. No biological data are available for assessment of compliance with the water quality objective for biostimulatory substances.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 15 samples exceeded the California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. No biological data are available for assessment of compliance with the 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 one of the applicable water quality objectives is not being exceeded and there is insufficient information to assess compliance with the other objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 8089
 
LOE ID: 8381
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
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 this station between 2001 and 2005. Concentrations of nitrate plus nitrite in 15 quarterly samples ranged from 0.2 to 1.12 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
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, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteeen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6885
 
Pollutant: Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station between 2001 and 2005. Concentrations of nitrate plus nitrite in 15 quarterly samples ranged from 0.2 to 1.12 mg/L. No data on algae or macrophytes are available for use in assessment of compliance with the biostimulatory substances objective.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include site-specific numerical objectives for "nitrate plus nitrite" for the Mojave River. The regionwide narrative objective for biostimulatory substances states:

“Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses.”
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteeen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8087
 
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 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 15 samples exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
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 8087
 
LOE ID: 6877
 
Pollutant: Nitrite
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 this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Two of 15 samples for NO2-N were below the detection level, and one was an estimated value. Nitrite concentrations in the remaining samples ranged from 0.005 to 0.018 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
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, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8083
 
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. Two of the samples exceed the water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region.
3. Two of fourteen samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 8083
 
LOE ID: 6870
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances: 2
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. The range of dissolved oxygen concentrations in 14 samples was 2.5 to 8.9 mg/L. Two samples were below the 4 mg/L minimum concentration.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The applicable water quality objective from Lahontan Basin Plan Table 3-6 is a one-day minimum of 4 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fourteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8102
 
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. There are no site-specific water quality objectives for phosphorus applicable to this station. No data on algae or macrophytes are available for assessment of compliance with the 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 available data for phosphate do not satisfy the data quantity requirement of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. There are no data on algae or macrophytes available for evaluation of compliance with the applicable 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 8102
 
LOE ID: 6883
 
Pollutant: Phosphate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 6
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2003 and 2005. Concentrations of filtered orthophosphate as P in 6 samples ranged from 0.013 to 0.052 mg/L. No data on algae or macrophytes are available for use in assessment of compliance with the biostimulatory substances objective.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include site-specific numerical objectives for phosphorus for the Mojave River. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Six quarterly samples (1 to 4 per year) were collected between 2003 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8103
 
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
Sources: Confined Animal Feeding Operations (NPS)
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. There is no site-specific water quality objective for phosphorus applicable to this station, and no data on algae or macrophytes are available for assessment of compliance with the 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 for total phoshorus 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 data on algae or macrophytes are available for assessment of compliance with the biostimulatory substances 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 insufficient information is available to assess compliance with the applicable water quality objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 8103
 
LOE ID: 6882
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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 sampled this station under the Region 6 SWAMP program between 2002 and 2005. Concentrations of total phosphorus in 11 quarterly samples ranged from 0.048 to 0.125 mg/L. Two samples were estimated values. No data on algae or macrophytes are available for use in assessment of compliance with the biostimulatory substances objective.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include site-specific numerical objectives for phosphorus for the Mojave River. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Eleven quarterly samples (2 to 4 per year) were collected between 2002 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8081
 
Pollutant: Specific Conductance
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

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

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and dissolved ion concentrations in streams of the Lahontan Region.
3. None of 15 field measurements of specific conductance exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
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 8081
 
LOE ID: 6873
 
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 this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Specific conductance in 15 field measurements measurements ranged from 322 to 832 uS/cm. Specific conductance in an additional laboratory measurement was 485 uS/cm. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
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, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly field measurements (2 to 4 per year) were collected between 2001 and 2005. One laboratory measurement was done on a water sample collected on March 19, 2003.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9102
 
Pollutant: Sulfates
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Five annual average datapoints exceed the site-specific water quality objective. However, listing is not recommended because the data are not temporally representative.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of fifteen samples exceeds the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five of five annual average datapoints exceeded the site-specific water quality objective and this exceeds the allowable frequency listed in Table 3.2.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because, although one of the applicable standards is being exceeded, the data are not temporally representative.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9102
 
LOE ID: 6867
 
Pollutant: Sulfates
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 5
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Sulfate concentrations in 15 individual samples ranged from 22.2 to 85.6 mg/L. Annual averages (based on 2 to 4 samples per year) ranged from 42.8 to 53.4 mg/L. The annual average objective was exceeded in five out of five years.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The site-specific objective from Lahontan Basin Plan Table 3-21 includes an annual average of 40 mg/L sulfate and a 90th percentile value of 100 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6866
 
Pollutant: Sulfates
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 this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Sulfate concentrations in 15 samples ranged from 22.2 to 85.6 mg/L. The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for sulfate is 250 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9105
 
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 the requirements of Listing Policy sections 3.10 and 6.1.5.9 are not met.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9105
 
LOE ID: 6872
 
Pollutant: Temperature, water
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Fifteen water temperature measurements ranged from 9 to 22.5 degrees Celsius.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The applicable language from the Lahontan Basin Plan's water quality objective is as follows: "The natural receiving water temperature of al l waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses.

For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly measurements of water temperature were taken between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9103
 
Pollutant: Total Dissolved Solids
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Fourteen of 15 samples exceed the site-specific water quality objective, which is a maximum value. However, listing is not recommended because the data are not temporally representative.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. (Quarterly samples do not capture the full range of seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. Fourteen of 15 samples exceed the site-specific water quality objective and this exceeds 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, although one of the applicable standards is being exceeded, the data are not temporally representative.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9103
 
LOE ID: 6869
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 14
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. The TDS concentrations in 15 samples ranged from 197 to 496 mg/L. Fourteen of 15 samples exceeded the maximum value objective.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The site- specific objective for Total Dissolved Solids (TDS) in the West Fork Mojave River (at Lower Narrows) in Lahontan Basin Plan Table 3-20 applies upstream to this station through the Tributary Rule. This objective is a maximum of 312 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
LOE ID: 6868
 
Pollutant: Total Dissolved Solids
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total 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 this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. The TDS concentrations in 15 samples ranged from 197 to 496 mg/L.The MCL was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The recommended MCL for Total Dissolved Solids (TDS) is 500 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8088
 
Pollutant: Total Kjeldahl Nitrogen (TKN)
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. There is no site-specific water quality objective for Total Kjeldahl Nitrogen (TKN), and no data are available on algae or macrophytes to facilitate assessment of compliance with the objective for "biostimlatory substances."

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3.There are no data on algae or macrophytes available for assessment of compliance with the biostimulatory substances objective.
. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because there is insufficient information to assess compliance with the applicable water quality objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 8088
 
LOE ID: 6884
 
Pollutant: Total Kjeldahl Nitrogen (TKN)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
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 sampled this station between 2002 and 2005. Concentrations of TKN in 11 quarterly samples ranged from 0.15 to 0.71 mg/L. No data on algae or macrophytes are available for use in assessment of compliance with the biostimulatory substances objective.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include site-specific numerical objectives for Total Kjeldahl Nitrogen (TKN) for the Mojave River. The regionwide narrative objective for biostimulatory substances states:

"Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Eleven quarterly samples (2 to 4 per year) were collected between 2002 and 2005.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
9104
 
Pollutant: pH
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects.

One line of evidence is available to support this decision. There are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because the data are insufficient to establish baseline and trend conditions under the requirements of Listing Policy section 3.10.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9104
 
LOE ID: 6886
 
Pollutant: pH
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 15
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station quarterly from 2001 to 2005 under the Region 6 SWAMP program. Field pH values in 15 measurements ranged from 7.1 to 7.9 units. An additional laboratory measurement on March 19, 2003 was 7.7 units.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's objective for pH states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units.

The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station, Mojave River at Upper Narrows, was sampled.
Temporal Representation: Fifteen quarterly pH measurements (2 to 4 per year) were taken between 2001 and 2005. An additional laboratory measurement was taken on March 19, 2003.
Environmental Conditions: The mainstem Mojave River originates below the Mojave River Forks Reservoir. The reservoir was constructed by damming the river’s two major tributaries, Deep Creek and the West Fork Mojave River. The river is intermittent and surface water is present in only a few locations.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):