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

Supporting Information

Regional Board 6 - Lahontan Region

Water Body Name: Mojave River (Mojave Forks Reservoir outlet to Upper Narrows)
Water Body ID: CAR6282000020080816195148
Water Body Type: River & Stream
 
DECISION ID
8035
 
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 Tertiary-Butyl Ether (MTBE) | 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 15 samples analyzed for each of 33 different organic pollutants were below detection levels. Per Listing Policy 6.1.5.5., 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 8035
 
LOE ID: 6774
 
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 Tertiary-Butyl Ether (MTBE) | 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 collected for each of 33 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 State 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; methyl tert butyl ether (MTBE), 13 ug/L (primary MCL) and 5 ug/L (secondary MCL); 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).
  Title 22. Division 4. Chapter 15. Sections 64400 et seq. California Code of Regulations
  Drinking Water Notification and Response Levels: An overview
 
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 33 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 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: 6800
 
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 Tertiary-Butyl Ether (MTBE) | 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: 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 collected for each of 33 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) acute and chronic freshwater aquatic life criteria for methyl tert butyl ether (MTBE) are 151,000 and 51,000 ug/L. The 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: National recommended water quality criteria: 2002. EPA-822-R-02-047 Washington, D.C. USEPA
  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 33 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 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
9026
 
Pollutant: Boron
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

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

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 14 samples exceeded the MCL. One of 5 annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
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 9026
 
LOE ID: 8299
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 14
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: .The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Boron concentrations in 14 quarterly samples ranged from 44 to 303 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 for boron is 1000 ug/L.
Objective/Criterion Reference: Compilation of Water Quality Goals
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station Mojave River below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fourteen quarterly samples 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 major source of boron in this watershed is probably natural geothermal activity. 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: 6745
 
Pollutant: Boron
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 1
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Boron concentrations in 14 quarterly samples ranged from 44 to 303 ug/L. Annual averages ranged from 54 to 261 mg/L. The annual average objective was exceeded in one of 5 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 boron concentration of 0. 2 mg/L (or 200 ug/L) and a 90th percentile level of 0.3 mg/L (or 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 below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fourteen quarterly samples 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 major source of boron in this watershed is probably natural geothermal activity. 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
8059
 
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 samples exceeded the MCL. None of five annual average values 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 8059
 
LOE ID: 6762
 
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 under the Region 6 SWAMP program between 2001 and 2005. Chloride concentrations in 15 quarterly samples ranged from 6.87 to 30.6 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 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 below [Mojave] Forks Reservoir, 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 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: 6746
 
Pollutant: Chloride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Chloride concentrations in 15 quarterly samples ranged from 6.87 to 30.6 mg/L. There were no violations of the annual average objective during the sampling period.
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 chloride concentration of 55 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 below [Mojave] Forks Reservoir, 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 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
8050
 
Pollutant: Dissolved oxygen saturation
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status.

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

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region.
3. None of six 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 8050
 
LOE ID: 6748
 
Pollutant: Dissolved oxygen saturation
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. Percent saturation of dissolved oxygen in 6 measurements ranged from 105 to 133 percent. The objective was not violated..
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's narrative objective states that percent saturation shall not be depressed by more than 10 percent and minimum dissolved oxygen concentration shall not be less than 80 percent saturation.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station Mojave River below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Six measurements of percent saturation were taken 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
9028
 
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 3.1 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. Four annual average datapoints exceed the site-specific water quality objective. Nine of the samples exceed the California Maximum Contaminant Level (MCL).

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification 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. Four of 5 annual average datapoints exceeded the site-specific objective. Nine of 14 samples samples exceeded the MCL. This exceeds the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because. although applicable water quality standards are being exceeded, the data are not temporally representative.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9028
 
LOE ID: 6767
 
Pollutant: Fluoride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 4
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. Fluoride concentrations in 14 quarterly samples ranged from 0.2 to 5.5 mg/L. The annual average objective was exceeded in four 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 (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 below [Mojave] Forks Reservoir, 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 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: 6766
 
Pollutant: Fluoride
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 14
Number of Exceedances: 9
 
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. Fluoride concentrations in 14 quarterly samples ranged from 0.2 to 5.5 mg/L. Nine of 14 samples exceeded the MCL.
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 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 below [Mojave] Forks Reservoir, 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 Mojave River is designated for both the Warm Freshwater Habitat and Cold Freshwater Habitat beneficial uses. The major source of fluoride upstream of this station is natural geothermal springs.
QAPP Information: The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
 
DECISION ID
8060
 
Pollutant: Nitrate as Nitrate (NO3)
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 exceeda 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 samples exceeded MCL or 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 8060
 
LOE ID: 6832
 
Pollutant: Nitrate as Nitrate (NO3)
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 under the Region 6 SWAMP program between 2001 and 2005. Samples were collected and analyzed for nitrite and nitrate plus nitrite, both expressed "as N." Nitrate was calculated by subtraction using these data. The maximum value in 15 quarterly samples was 0.062 mg/L "as N" or 0.289 mg/L "as nitrate." 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 below [Mojave] Forks Reservoir, 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 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: 6831
 
Pollutant: Nitrate as Nitrate (NO3)
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 under the Region 6 SWAMP program between 2001 and 2005. Samples were collected and analyzed for nitrite and nitrate plus nitrite, both expressed "as N." Nitrate was calculated by subtraction using these data. The maximum value in 15 quarterly samples was 0.065 mg/L "as N" or 0.289 mg/L "as nitrate." The objective was not exceeded.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan does not include a site-specific objective for nitrogen at the "Mojave River at Forks" station (Basin Plan Table 3-21). The objective for station 2 in Table 3-20 applies upstream under the Tributary Rule. It is a maximum "nitrate as nitrate" value of 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 below [Mojave] Forks Reservoir, 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 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
9033
 
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 lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the California 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 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 MCL 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 water quality objective for biostimulatory substance.
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 becauseone of the applicable water quality standards is not being exceeded and there are no biological data for assessment of compliance with the other standard.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9033
 
LOE ID: 6835
 
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 under the Region 6 SWAMP program between 2001 and 2005. Concentrations of nitrate plus nitrite in 5 of 15 quarterly samples were below the detection level. The remaining samples ranged from 0.008 to 0.505 mg/L. No data were available on algae or macrophytes for evaluation 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 a site-specific objective for nitrate plus nitrite. The narrative water quality 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 below [Mojave] Forks Reservoir, 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 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: 8302
 
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 under the Region 6 SWAMP program between 2001 and 2005. Concentrations of nitrate plus nitrite in 5 of 15 quarterly samples were below the detection level. The remaining samples ranged from 0.008 to 0.505 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 below [Mojave] Forks Reservoir, 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 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
9038
 
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 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 California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9038
 
LOE ID: 6833
 
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 under the Region 6 SWAMP program between 2001 and 2005. Six of 15 quarterly samples for NO2-N were below the detection level. Nitrite concentrations in the remaining samples ranged from 0.001 to 0.009 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 nitrate is 1 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 below [Mojave] Forks Reservoir, 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 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
8049
 
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. 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 diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region.
3. None 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 8049
 
LOE ID: 6747
 
Pollutant: Oxygen, Dissolved
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 14
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. The range of dissolved oxygen concentrations in 14 quarterly samples was 6.3 to 11.9 mg/L. The objective was not violated.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The water quality objective from Lahontan Basin Plan Table 3-6 is a one day minimum dissolved oxygen concentration of 4 mg/L.
Objective/Criterion Reference: 2007. Water Quality Control Plan for the Lahontan Region (as amended).
  2007. SWAMP Data for the Mojave River Watershed
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One station Mojave River below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fourteen quarterly samples 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
8051
 
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 objectives for phosphorus in the Mojave River, and the narrative objective for biostimulatory substances applies. There are no data on algae or macrophytes available to determine whether excess productivity due to phosphorus occurred

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. No biological data are available for assessment whether the 6 chemical samples exceeded 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 no biological data are available for assessment of compliance with the applicable water quality objective..
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 8051
 
LOE ID: 6813
 
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 PO4-P in six quarterly samples ranged from 0.03 to 0.058 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 below [Mojave] Forks Reservoir, 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
9039
 
Pollutant: Phosphorus
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: New Decision
Revision Status Revised
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. There are no biological data for assessment whether any of the chemical 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. There are no biological data for use in 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 there are no biological data for use with the chemical data in assessing compliance with the applicable water quality objective.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9039
 
LOE ID: 6812
 
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 0.04 to 0.19 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 below [Mojave] Forks Reservoir, 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
9067
 
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 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 3.2 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 9067
 
LOE ID: 6750
 
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 under the Region 6 SWAMP program between 2001 and 2005. Fifteen quarterly field measurements of specific conductance ranged from 190 to 615 uS/cm. Specific conductance levels in an additional two laboratory measurements taken in 2003 were 246 and 328 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 below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fifteen quarterly field measurements of specific conductance were taken between 2001 and 2005. Two laboratory measurements were taken in March and June 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 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
9037
 
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 exceed the California Maximum Contaminant Level (MCL). Three of five annual average datapoints exceed the site-specific water quality objective.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. None of 15 samples exceeded the MCL. Three of five annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
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 9037
 
LOE ID: 6749
 
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 under the Region 6 SWAMP program between 2001 and 3005. Sulfate concentrations in 15 quarterly samples ranged from 2.2 to 130 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 below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fifteen quarterly samples 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 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: 6751
 
Pollutant: Sulfates
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Dissolved
 
Beneficial Use: Cold Freshwater Habitat
 
Number of Samples: 5
Number of Exceedances: 3
 
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 3005. Sulfate concentrations in 15 quarterly samples ranged from 2.2 to 130 mg/L. Annual averages, based on 2 to 4 samples per year, ranged from 14.4 to 94.6 mg/L. The site-specific objective was exceeded in three 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 includeds an annual average sulfate concentration of 35 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 below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fifteen quarterly samples 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 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
9070
 
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 available data are not sufficient to meet the requirements of Listing Policy sections 3.10 and 6.1.5.9.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9070
 
LOE ID: 6764
 
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 under the Region 6 SWAMP program between 2001 and 2005. Fifteen quarterly measurements of water temperature ranged from 9 to 22.5 degrees Celsius.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The relevant language from the Lahontan Basin Plan's narrative water quality objective is: "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 below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fifteen quarterly temperature measurements (two to four per year) 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 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
9035
 
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 15 samples exceeds the California Maximum Contaminant Level (MCL). Five of the samples exceed the site-specific water quality objective, which is expressed as a maximum value. 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 variation expected in streamflow and constituent concentrations in streams of the Lahontan Region.
3. None of 15 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five of 15 samples exceeded the site-specific 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 9035
 
LOE ID: 6752
 
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: 5
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: The U.S. Geological Survey sampled this station under the Region 6 SWAMP program between 2001 and 2005. TDS concentrations in 15 SWAMP samples ranged from 171 to 386 mg/L. Five samples exceeded the 312 mg/L maximum.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's Table 3-21 does not contain a site-specific objective for Total Dissolved Solids (TDS) at the “Mojave River below Forks” station. However, the objective for the West Fork Mojave River (at Lower Narrows) in Basin Plan Table 3-20 applies upstream through the Tributary Rule. This objective is a maximum of 312 mg/L TDS.
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 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: 6753
 
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 under the Region 6 SWAMP program between 2001 and 2005. TDS concentrations in 15 SWAMP samples ranged from 171 to 386 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 below [Mojave] Forks Reservoir was sampled.
Temporal Representation: Fifteen quarterly samples 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
9041
 
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 are no biological data available to asses whether any of the chemical samples exceed the water quality objective for biostimulatory substances.

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

This conclusion is based on the staff findings that:
1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy.
2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.
3. No biological data are available to assess whether any of the 11 chemical samples exceeded 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 no biological data are available to determine whether the applicable water quality objective is being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9041
 
LOE ID: 6834
 
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 under the Region 6 SWAMP program between 2002 and 2005. Concentrations of TKN in 11 quarterly samples ranged from 0.19 to 0.51 mg/L. No data were available on algae or macrophytes for evaluation 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 a site-specific objective for Total Kjeldahl Nitrogen (TKN). The narrative water quality 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 below [Mojave] Forks Reservoir, 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
9069
 
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 define baseline/trend conditions as required under Listing Policy section 3.10.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 9069
 
LOE ID: 6899
 
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 under the Region 6 SWAMP program between 2001 and 2005. In 15 quarterly field measurements, pH ranged from 7.5 to 8.9 units. Two of 15 pH values were higher than 8.5 units. Two laboratory measurements were taken in 2003; one of the pH values was an estimate and the other was 8 units.
Data Reference: 2007. SWAMP Data for the Mojave River Watershed
 
Water Quality Objective/Criterion: The Lahontan Basin Plan's regionwide objective for pH is as follows: "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: 2007. SWAMP Data for the Mojave River Watershed
 
Spatial Representation: One station, Mojave River below [Mojave] Forks Reservoir, was sampled.
Temporal Representation: Fifteen quarterly field measurements of pH (2 to 4 per year) were taken between 2001 and 2005. Two laboratory measurements were taken in March and June 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 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):