# Final 2008 California 303(d)/305(b) Integrated Report

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Gilsizer Slough (from Yuba City to downstream of Township Road, Sutter County)
Water Body ID: | CAR5203000020080702172323
Water Body Type: | River & Stream

DECISION ID | 10047
Pollutant: | Ammonia
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 listing under sections 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Data is available from 1 line of evidence for this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is not sufficient justification for placing this water segment-pollution combination on the section 303(d) list. The recommendation is based on staff findings that 0 of 15 available concentrations exceeded the USEPA Health Advisory for Ammonia and this does not exceed the allowable frequency using Table 3.1 of the Listing Policy. The recommendation is based on staff findings that 0 of 14 available concentrations exceeded the USEPA Freshwater Aquatic Life Protection Criteria Maximum Concentration and this does not exceed the allowable frequency using Table 3.1 of the Listing Policy. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 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 10047

LOE ID: | 8793
Pollutant: | Ammonia
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 14
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Zero of the 14 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation guideline for Ammonia.
Data Reference: | SWAMP data entered by SWRCB into BDAT database
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances. (CRWQCB, 2006)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Ammonia levels should not to exceed the calculated limit. Freshwater Aquatic Life Protection (Salmonid present) Criteria Maximum Concentration (CMC) (1-hour Average (mg N/L)) calculated based on the following formula: CMC = (0.275/(1 + 107.204-pH)) + (39.0/(1 + 10pH-7.204)) which incorporates pH (US EPA, 2005: Appendix C)
Guideline Reference: | 1999 Update of Ambient Water Quality Criteria for Ammonia
Spatial Representation: | Samples were collected at Gilsizer Slough @ O'banion Road.
Temporal Representation: | The samples were collected from Dec 7 2000 to Mar 18 2002
Environmental Conditions: |
QAPP Information: | Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s):
LOE ID: | 20460
Pollutant: | Ammonia
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: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | 0 of the 15 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for Ammonia.
Data Reference: | SWAMP data entered by SWRCB into BDAT database
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances. (CRWQCB, 2006)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Ammonia levels should not exceed 30 mg/L (USEPA Health Advisory)
Guideline Reference: | 2006 edition of the drinking water standards and health advisories. EPA 822-R-03-013
Spatial Representation: | Samples were collected at Gilsizer Slough @ O'banion Road.
Temporal Representation: | The samples were collected from Dec 7 2000 to Mar 18 2002
Environmental Conditions: |
QAPP Information: | Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s):

DECISION ID | 14523
Pollutant: | Disulfoton
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. Three lines of evidence are available in the administrative record to assess this pollutant. One water samples contained disulfoton at a concentration that exceeds the Evaluation Guideline for the narrative toxicity 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 18 water samples contained disulfoton at a concentration that exceeds the Evaluation Guideline value of 0.05 ug/L and, therefore, only one sample exceeded the narrative toxicity 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 14523

LOE ID: | 26146
Pollutant: | Disulfoton
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Seven water samples were collected from Gilsizer Slough, under the Irrigated Lands Regulatory Program, between February and September 2006. Zero of the 7 water samples contained disulfoton at concentrations that exceed the Evaluation Guideline of 0.05 ug/L.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | USEPA National Ambient Water Quality Disulfoton Criterion for freshwater aquatic life protection, maximum concentration of 0.05 ug/L.
Guideline Reference: | National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation: | Water samples were collected from Gilsizer Slough at South Township Road.
Temporal Representation: | Water samples were collected from Gilsizer Slough on February 28, March 16, May 24, June 21, July 19, August 16, and September 20, 2006.
Environmental Conditions: |
QAPP Information: | Data Quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826 ) requirements.
QAPP Information Reference(s):
LOE ID: | 22465
Pollutant: | Disulfoton
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Three water samples were collected from Gilsizer Slough at Obanion Road on 12 July 2004, 16 November 2004, and on 12 April 2005. None of the water samples contained disulfoton at concentrations that exceed the Evaluation Guideline of 0.05 ug/L
Data Reference: | Surface Water database (SWDB) for Central Valley waterbodies, 2000-2005
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses (CVRWQCB, 2007). All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life (CVRWQCB, 2007).
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | USEPA National Ambient Water Quality disulfoton criterion for freshwater aquatic life protection, maximum concentration of 0.05 ug/L.
Guideline Reference: | National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation: | Samples were collected from Gilsizer Slough at Obanion Road.
Temporal Representation: | Water samples were collected from Gilsizer Slough on 12 July 2004, 16 November 2004, and on 12 April 2005.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Minimum requirements for the Surface Water Database are: Name of the sampling agency or organization Date that each sample was collected Date of each sample analysis County where samples were taken Detailed sampling location information (including latitude and longitude or township/range/section if available), detailed map or description of each sampling site (i.e., address, cross roads, etc.) Name or description of water body sampled Name of the active ingredient analyzed for; concentration detected (with unit of measurement), and limit of quantitation Description of analytical QA/QC plan, or statement that no formal plan exists Additional optional requirements are included on DPRs webpage at http://www.cdpr.ca.gov/docs/emon/surfwtr/caps/req.htm
QAPP Information Reference(s): | Surface Water database (SWDB) for Central Valley waterbodies, 2000-2005
LOE ID: | 26145
Pollutant: | Disulfoton
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Eight water samples were collected from Gilsizer Slough, under the Pesticide TMDL program, between January and April 2006. One of the 8 water samples contained disulfoton at a concentration that exceeds the Evaluation Guideline of 0.05 ug/L.
Data Reference: | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | USEPA National Ambient Water Quality disulfoton criterion for freshwater aquatic life protection, maximum concentration of 0.05 ug/L.
Guideline Reference: | National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency
Spatial Representation: | Water samples were collected from Gilsizer Slough at South Township Road.
Temporal Representation: | Water samples were collected from Gilsizer Slough on 14 and 15 January 2006, 27 and 28 February 2006, 14 and 28 March 2006, and 11 and 25 April 2006.
Environmental Conditions: |
QAPP Information: | Data Quality: Good. All sampling, analysis and QA/QC protocols are described in a QAPP (Calanchini et al., 2006).
QAPP Information Reference(s):

DECISION ID | 14524
Pollutant: | Diuron
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. One 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 8 samples exceeded the narrative toxicity 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 14524

LOE ID: | 22467
Pollutant: | Diuron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Four water samples were collected from Gilsizer Slough biweekly in March and April 2006.Zero of four concentrations exceeded the maximum concentration of 1.3 ug/L.
Data Reference: | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses (CVRWQCB, 2007).All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life (CVRWQCB, 2007).
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | The Board will use the best available technical information to evaluate compliance with the narrative objectives. Other available technical information on the pesticide (such as Lowest Observed Effect Concentrations and No Observed Effect Levels), the water bodies and organisms involved will be evaluated to determine if lower concentrations are required to meet the narrative objectives. (CRWQCB, 2006).The 96 hour EC50 for the most sensitive species is 1.3 ug/L (ECOTOX, 2008).
Guideline Reference: | Ecotox database, http://cfpub.epa.gov/ecotox/
Spatial Representation: | Samples were collected at Gilsizer Slough at Nuestro Road.
Temporal Representation: | Samples were collected biweekly during March and April, 2006.
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Calanchini, H. 2006. Quality Assurance Project Plan, Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. John Muir Institute of the Environment, U.C. Davis. Davis, CA.
QAPP Information Reference(s): | Quality Assurance Project Plan. Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. Final. SWAMP Project ID 02TM5001 (Revision 0.0). John Muir Institute of the Environment, U.C. Davis. Davis, CA. January 26, 2006
LOE ID: | 22466
Pollutant: | Diuron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 4
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Four water samples were collected from Gilsizer Slough during two storms in January and February 2006.One of four concentrations exceeded the maximum concentration of 1.3 ug/L.
Data Reference: | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses (CVRWQCB, 2007).All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life (CVRWQCB, 2007).
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | The Board will use the best available technical information to evaluate compliance with the narrative objectives. Other available technical information on the pesticide (such as Lowest Observed Effect Concentrations and No Observed Effect Levels), the water bodies and organisms involved will be evaluated to determine if lower concentrations are required to meet the narrative objectives. (CRWQCB, 2006).The 96 hour EC50 for the most sensitive species is 1.3 ug/L (ECOTOX, 2008).
Guideline Reference: | Ecotox database, http://cfpub.epa.gov/ecotox/
Spatial Representation: | Samples were collected at Gilsizer Slough at Nuestro Road.
Temporal Representation: | Samples were collected at daily intervals during two storm events in 2006.
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Calanchini, H. 2006. Quality Assurance Project Plan, Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. John Muir Institute of the Environment, U.C. Davis. Davis, CA.
QAPP Information Reference(s): | Quality Assurance Project Plan. Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. Final. SWAMP Project ID 02TM5001 (Revision 0.0). John Muir Institute of the Environment, U.C. Davis. Davis, CA. January 26, 2006

DECISION ID | 14526
Pollutant: | Escherichia coli (E. Coli)
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 lines of evidence are 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of 7 samples exceeded the E. Coli 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 14526

LOE ID: | 22536
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 7
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | The Sac Valley Water Quality Coalition collected 7 samples from February 2006 to September 2006. Two out of 7 samples exceeded the evaluation objective.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. The objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
| Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
Evaluation Guideline: | The USEPA E. Coli objective of 235/100 mL in any single sample (USEPA 1986).
Guideline Reference: | Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
Spatial Representation: | Samples were collected from Gilsizer Slough.
Temporal Representation: | Sampling occurred from February 2006 to September 2006.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):

DECISION ID | 14525
Pollutant: | Malathion
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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of 11 samples exceeded the 4-day average concentrations exceeded criterion continuous concentration (CCC) and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. In addition, 0 of 13 samples exceeded the 1-hour maximum concentration 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 14525

LOE ID: | 22533
Pollutant: | Malathion
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | 5 water samples were collected from Gilsizer Slough from February 2000 through May 2005, representing 5 4-day average concentrations and 5 1-hour average concentrations.0 of 5 4-day average concentrations exceeded the 4-day maximum concentration guideline of 0.1 ug/L.0 of 5 1-hour average concentrations exceeded the maximum 1-hour concentration of 0.43 ug/L.
Data Reference: | Surface Water database (SWDB) for Central Valley waterbodies, 2000-2005
| Correspondence between the Department of Pesticide Regulation and Central Valley Regional Water Quality Control Board regarding water quality data for waterbodies in the Central Valley
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses (CVRWQCB, 2007).All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life (CVRWQCB, 2007).
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
| Quality Criteria for Water. USEPA Office of Water and Hazardous Materials. Washington, D.C
Evaluation Guideline: | US EPA recommended criterion continuous concentration (CCC) of 0.1 ug/L (US EPA, 1976). California Department of Fish and Game Hazard Assessment Criterion is 0.43 ug/L for criterion maximum concentration (CMC) (CDFG, 1998)
Guideline Reference: | Hazard Assessment of the Insecticide Malathion to Aquatic Life in the Sacramento-San Joaquin River System. California Department of Fish and Game. Office of Spill Prevention and Response Administrative Report 98-2
Spatial Representation: | Samples were collected from Gilsizer Slough at OBanion Road.
Temporal Representation: | Samples were collected at variable intervals from February 2000 through April 2005.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Minimum requirements for the CDPR Surface Water Database are: Name of the sampling agency or organization, Date that each sample was collected, Date of each sample analysis, County where samples were taken, Detailed sampling location information (including latitude and longitude or township/range/section if available), detailed map or description of each sampling site (i.e., address, cross roads, etc.), Name or description of water body sampled, Name of the active ingredient analyzed for; concentration detected (with unit of measurement), and limit of quantitation, Description of analytical QA/QC plan, or statement that no formal plan exists. Additional optional requirements are included on DPR's webpage at http://www.cdpr.ca.gov/docs/emon/surfwtr/caps/req.htm
QAPP Information Reference(s): | Standard Operating Procedure for Conducting Surface Water Monitoring for Pesticides
LOE ID: | 22534
Pollutant: | Malathion
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 6
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | 8 water samples were collected from Gilsizer Slough from January and April 2006, representing 6 4-day average concentrations and 8 1-hour average concentrations.0 of 6 available 4-day average concentrations exceeded the 4-day maximum concentration guideline of 0.1 ug/L.0 of 8 available 1-hour average concentrations exceeded the maximum 1-hour concentration of 0.43 ug/L.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses (CVRWQCB, 2007).All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life (CVRWQCB, 2007).
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
| Quality Criteria for Water. USEPA Office of Water and Hazardous Materials. Washington, D.C
Evaluation Guideline: | US EPA recommended criterion continuous concentration (CCC) of 0.1 ug/L (US EPA, 1976). California Department of Fish and Game Hazard Assessment Criterion is 0.43 ug/L for criterion maximum concentration (CMC) (CDFG, 1998)
Guideline Reference: | Hazard Assessment of the Insecticide Malathion to Aquatic Life in the Sacramento-San Joaquin River System. California Department of Fish and Game. Office of Spill Prevention and Response Administrative Report 98-2
Spatial Representation: | Samples were collected from Gilsizer Slough at South Township Road.
Temporal Representation: | Samples were collected at variable intervals (e.g. daily, biweekly) from January to April 2006.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):

DECISION ID | 14664
Pollutant: | Methidathion
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. Three lines of evidence are available in the administrative record to assess this pollutant. None of water samples contained methidathion at concentrations that exceed the Evaluation Guideline for the narrative toxicity 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of 20 water samples contained methidathion at concentrations that exceed the methidathion Evaluation Guideline value of 0.22 ug/L and, therefore, none of the samples exceeded the narrative toxicity 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 14664

LOE ID: | 26149
Pollutant: | Methidathion
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Five water samples were collected from Gilsizer Slough. None of the water samples contained methidathion at concentrations that exceed the Evaluation Guideline of 0.22 ug/L
Data Reference: | Surface Water database (SWDB) for Central Valley waterbodies, 2000-2005
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses (CVRWQCB, 2007). All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life (CVRWQCB, 2007).
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | USEPA National Ambient Water Quality disulfoton criterion for freshwater aquatic life protection, maximum concentration of 0.05 ug/L.
Guideline Reference: | National Recommended Water Quality Criteria. United States Environmental Protection Agency. Office of Water. Office of Science and Technology. 4304T The Blue Book
Spatial Representation: | Water samples were collected from Gilsizer Slough at Richland (1 sample), Bogue Road (1 sample), and Obanion Road (3 samples).
Temporal Representation: | Water samples were collected from Gilsizer Slough on 23 February 2000 (1 sample each at Richland and Bogue Road), and on 12 July 2004, 16 November 2004, and 12 April 2005 (OBanion Road).
Environmental Conditions: |
QAPP Information: | Data quality: Good. Minimum requirements for the Surface Water Database are: Name of the sampling agency or organization Date that each sample was collected Date of each sample analysis County where samples were taken Detailed sampling location information (including latitude and longitude or township/range/section if available), detailed map or description of each sampling site (i.e., address, cross roads, etc.) Name or description of water body sampled Name of the active ingredient analyzed for; concentration detected (with unit of measurement), and limit of quantitation Description of analytical QA/QC plan, or statement that no formal plan exists Additional optional requirements are included on DPRs webpage at http://www.cdpr.ca.gov/docs/emon/surfwtr/caps/req.htm
QAPP Information Reference(s): | Surface Water database (SWDB) for Central Valley waterbodies, 2000-2005
LOE ID: | 26147
Pollutant: | Methidathion
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Eight water samples were collected from Gilsizer Slough between January and April 2006. Zero of the 8 water samples contained methidathion at concetrations that exceeded the Evaluation Guideline of 0.22 ug/L.
Data Reference: | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Where valid testing has developed 96 hour LC50 values for aquatic organisms (the concentration that kills one half of the test organisms in 96 hours), the Board will consider one tenth of this value for the most sensitive species tested as the upper limit (daily maximum) for the protection of aquatic life. Other available technical information on the pesticide (such as Lowest Observed Effect Concentrations and No Observed Effect Levels), the water bodies and the organisms involved will be evaluated to determine if lower concentrations are required to meet the narrative objectives. The 96-hour LC50 for methidathion for the most sensitive freshwater species tested (Ceriodaphnia dubia , a water flea), is 2.2 ug/L. The Evaluation Guideline is based on one-tenth of the 96-hour LC50 and, therefore the Evaluation Guideline value is 0.22 ug/L.
Guideline Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
| ECOTOX database, aquatic data. U. S. Environmental Protection Agency
Spatial Representation: | Water samples were collected from Gilsizer Slough at South Township Road.
Temporal Representation: | Water samples were collected from Gilsizer Slough on 14 and 15 January 2006, 27 and 28 February 2006, 14 and 28 March 2006, and 11 and 25 April 2006.
Environmental Conditions: |
QAPP Information: | Data Quality: Good. All sampling, analysis and QA/QC protocols are described in a QAPP (Calanchini et al., 2006).
QAPP Information Reference(s): | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
LOE ID: | 26148
Pollutant: | Methidathion
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Seven water samples were collected from Gilsizer Slough, under the Irrigated Lands Regulatory Program, between February and September 2006. Zero of the 7 water samples contained methidathion at concentrations that exceed the Evaluation Guideline of 0.22 ug/L.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Where valid testing has developed 96 hour LC50 values for aquatic organisms (the concentration that kills one half of the test organisms in 96 hours), the Board will consider one tenth of this value for the most sensitive species tested as the upper limit (daily maximum) for the protection of aquatic life. Other available technical information on the pesticide (such as Lowest Observed Effect Concentrations and No Observed Effect Levels), the water bodies and the organisms involved will be evaluated to determine if lower concentrations are required to meet the narrative objectives. The 96-hour LC50 for methidathion for the most sensitive freshwater species tested (Ceriodaphnia dubia , a water flea), is 2.2 ug/L. The Evaluation Guideline is based on one-tenth of the 96-hour LC50 and, therefore the Evaluation Guideline value is 0.22 ug/L.
Guideline Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Spatial Representation: | Water samples were collected from Gilsizer Slough at South Township Road.
Temporal Representation: | Water samples were collected from Gilsizer Slough on February 28, March 16, May 24, June 21, July 19, August 16, and September 20, 2006.
Environmental Conditions: |
QAPP Information: | Data Quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826 ) requirements.
QAPP Information Reference(s):

DECISION ID | 14522
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 lines of evidence are 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Four of 5 samples fell below the criteria outlined in the Basin Plan 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 14522

LOE ID: | 22535
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 4
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | 5 samples were taken from the Gilsizer Slough from March to September 2006. 4 samples exceeds Water Quality Objectives for minimum dissolved oxygen concentration (7 mg/L) and 3 sample exceeds 5 mg/L.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | Sacramento/San Joaquin River Basin Plan (CVRWQCB, 2007a) (COLD), Minimum Dissolved Oxygen concentration of 7mg/L(SPWN), Minimum Dissolved Oxygen concentration of 7 mg/L(WARM), Minimum Dissolved Oxygen concentration of 5 mg/L
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected from Gilsizer Slough (sampling site Lat. 39.0, and Lang. -121.67).
Temporal Representation: | Samples were collected between March and September 2006 at monthly interval.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):

DECISION ID | 14527
Pollutant: | Sediment Toxicity
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 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of 2 samples exceeded the narrative toxicity 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 14527

LOE ID: | 22520
Pollutant: | Toxicity
LOE Subgroup: | Toxicity
Matrix: | Sediment
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Zero of two samples tested with Hyalella azteca were toxic.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances. (CVRWQCB, 2007)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Statistically significant difference from control sediment using Dunnett's test in 10-day Hyalella azteca sediment toxicity tests. Arcsin squareroot transformation was used when necessary to meet the assumptions of normality and homogeneity of variance. Steel's Many-One Rank Test was used for comparison to control if these assumptions were not met after transformation.
Guideline Reference: | Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064
Spatial Representation: | Samples were collected from Gilsizer Slough.
Temporal Representation: | Samples were collected from March - September 2006
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):

DECISION ID | 10048
Pollutant: | Specific Conductivity
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 listing under sections 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Data is available from 1 line of evidence for this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is not sufficient justification for placing this water segment-pollution combination on the section 303(d) list. The recommendation is based on staff findings that 3 of 15 available concentrations exceeded the water quality objective and this does not exceed the allowable frequency using Table 3.2 of the Listing Policy. Table 3.2 of the listing policy recommends listing if a sample size of 15 has 5 or more samples that exceed the evaluation criteria.
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 10048

LOE ID: | 21079
Pollutant: | Specific Conductivity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 3
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Three of the 15 samples collected by the Surface Water Ambient Monitoring Program exceeded the "recommended" Secondary MCL of 900 uS/cm for electrical conductivity
Data Reference: | SWAMP data entered by SWRCB into BDAT database
Water Quality Objective/Criterion: | The secondary MCLs for electrical conductivity provide a range of values including a recommended level (900 uS/cm), upper level (1600 uS/cm) and a short-term level (2200 uS/cm). The recommended level of 900 uS/cm was used as it is intended to be protective of all drinking water uses
Objective/Criterion Reference: | California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring. http://www.cdph.ca.gov/certlic/drinkingwater/Pages/Lawbook.aspx
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected from Gilsizer Slough at O'Banion Road
Temporal Representation: | The samples were collected between December 7, 2000 and July 30, 2002
Environmental Conditions: |
QAPP Information: | Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s):

DECISION ID | 14528
Pollutant: | Unknown Toxicity
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. Three lines of evidence are available in the administrative record to assess this pollutant. One 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 7 samples tested with ceriodaphnia exceeded the narrative toxicity objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. In addition, 0 of 7 samples tested with fathead minnow exceeded the narrative toxicity objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. Lastly, 0 of 7 samples tested with selenastrum exceeded the narrative toxicity 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 14528

LOE ID: | 22519
Pollutant: | Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Zero of seven samples tested with Pimephales promelas were toxic.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances. (CVRWQCB, 2007)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Statistically significant difference from control using a t-test with 4-day acute-style toxicity tests.
Guideline Reference: | Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-821-R-02-012
Spatial Representation: | Samples were collected from Gilsizer Slough.
Temporal Representation: | Samples were collected from February - September 2006
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):
LOE ID: | 22518
Pollutant: | Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 1
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | One of seven samples tested with Ceriodaphnia dubia were toxic and violated the narrative toxicity objective.The sample collected 16 March 2006 exhibited 80% survival (80% of control).
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances. (CVRWQCB, 2007)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Statistically significant difference from control using a t-test with 4-day acute-style toxicity tests.
Guideline Reference: | Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-821-R-02-012
Spatial Representation: | Samples were collected from Gilsizer Slough.
Temporal Representation: | Samples were collected from February - September 2006
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):
LOE ID: | 22532
Pollutant: | Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 0
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Zero of seven samples tested with Selenastrum capricornutum were toxic.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances. (CVRWQCB, 2007)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Statistically significant difference from control using a t-test with 4-day chronic-style toxicity tests.
Guideline Reference: | Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fourth Edition. U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-821-R-02-013
Spatial Representation: | Samples were collected from Gilsizer Slough.
Temporal Representation: | Samples were collected from February - September 2006
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):

DECISION ID | 12937
Pollutant: | Diazinon
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture
Expected TMDL Completion Date: | 2021
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. Four lines of evidence are available in the administrative record to assess this pollutant. Four samples exceed the narrative toxicity water quality objective. 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Four of eighteen available calculated 4-day average diazinon concentrations exceeded the 4-day average diazinon criterion, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Three of twenty available 1-hour average diazinon concentrations exceeded the 1-hour average diazinon criterion, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 5. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 12937

LOE ID: | 22479
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Seven water samples were collected from Gilsizer Slough monthly from February through September in 2006, representing seven calculated 4-day average diazinon concentrations and seven 1-hour average diazinon concentrations. Zero of the seven available 1-hour average diazinon concentrations exceeded the 1-hour average diazinon criterion of 0.160 ug/L. One of the seven available calculated 4-day average diazinon concentrations exceeded the 4-day average diazinon criterion of 0.100 ug/L.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
| Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | California Department of Fish and Game Hazard Assessment Diazinon Criteria: 0.160 ug/L as a 1-hour average concentration, and 0.100 ug/L as a 4-day average concentration, not to be exceeded more than once every three years.
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Samples were collected from Gilsizer Slough at George Washington Road.
Temporal Representation: | Samples were collected monthly from February through September (not April) 2006.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)
QAPP Information Reference(s):
LOE ID: | 22468
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Four water samples were collected from Gilsizer Slough during two winter storms in 2006, representing two calculated 4-day average diazinon concentrations and four 1-hour average diazinon concentrations. Two of the four available 1-hour average diazinon concentrations exceeded the 1-hour average diazinon criterion of 0.160 ug/L. One of the two available calculated 4-day average diazinon concentrations exceeded the 4-day average diazinon criterion of 0.100 ug/L.
Data Reference: | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | California Department of Fish and Game Hazard Assessment Diazinon Criteria: 0.160 ug/L as a 1-hour average concentration, and 0.100 ug/L as a 4-day average concentration, not to be exceeded more than once every three years.
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Samples were collected from Gilsizer Slough at Nuestro Road.
Temporal Representation: | Samples were collected at daily intervals during two storm events in 2006.
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Calanchini, H. 2006. Quality Assurance Project Plan, Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. John Muir Institute of the Environment, U.C. Davis. Davis, CA.
QAPP Information Reference(s): | Quality Assurance Project Plan. Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. Final. SWAMP Project ID 02TM5001 (Revision 0.0). John Muir Institute of the Environment, U.C. Davis. Davis, CA. January 26, 2006
LOE ID: | 22478
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Five water samples were collected from Gilsizer Slough in 2000, 2004 and 2005, representing five calculated 4-day average diazinon concentrations and five 1-hour average diazinon concentrations. One of the five available 1-hour average diazinon concentrations exceeded the 1-hour average diazinon criterion of 0.160 ug/L. Two of the five available calculated 4-day average diazinon concentrations exceeded the 4-day average diazinon criterion of 0.100 ug/L.
Data Reference: | Surface Water database (SWDB) for Central Valley waterbodies, 2000-2005
| Correspondence between the Department of Pesticide Regulation and Central Valley Regional Water Quality Control Board regarding water quality data for waterbodies in the Central Valley
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | California Department of Fish and Game Hazard Assessment Diazinon Criteria: 0.160 ug/L as a 1-hour average concentration, and 0.100 ug/L as a 4-day average concentration, not to be exceeded omre than once every three years.
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Samples were collected from Gilsizer Slough at Bogue Road, at OBanion Road, and at Richland.
Temporal Representation: | Two samples were collected in February 2000, one sample was collected in April 2005, and two samples were collected in July and November 2004.
Environmental Conditions: |
QAPP Information: | Data quality: Fair. Minimum requirements for the CDPR Surface Water Database are: Name of the sampling agency or organization, Date that each sample was collected, Date of each sample analysis, County where samples were taken, Detailed sampling location information (including latitude and longitude or township/range/section if available), detailed map or description of each sampling site (i.e., address, cross roads, etc.), Name or description of water body sampled, Name of the active ingredient analyzed for; concentration detected (with unit of measurement), and limit of quantitation, Description of analytical QA/QC plan, or statement that no formal plan exists. Additional optional requirements are included on DPR's webpage at http://www.cdpr.ca.gov/docs/emon/surfwtr/caps/req.htm
QAPP Information Reference(s): | Standard Operating Procedure for Conducting Surface Water Monitoring for Pesticides
LOE ID: | 22477
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Four water samples were collected from Gilsizer Slough biweekly from March through April in 2006, representing four calculated 4-day average diazinon concentrations and four 1-hour average diazinon concentrations. Zero of the four available 1-hour average diazinon concentrations exceeded the 1-hour average diazinon criterion of 0.160 ug/L. Zero of the four available calculated 4-day average diazinon concentrations exceeded the 4-day average diazinon criterion of 0.100 ug/L.
Data Reference: | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
| Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | California Department of Fish and Game Hazard Assessment Diazinon Criteria: 0.160 ug/L as a 1-hour average concentration, and 0.100 ug/L as a 4-day average concentration, not to be exceeded more than once every three years.
Guideline Reference: | Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game
Spatial Representation: | Samples were collected at Gilsizer Slough at Nuestro Road.
Temporal Representation: | Samples were collected biweekly during March and April, 2006.
Environmental Conditions: |
QAPP Information: | Data quality: Excellent. Calanchini, H. 2006. Quality Assurance Project Plan, Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. John Muir Institute of the Environment, U.C. Davis. Davis, CA.
QAPP Information Reference(s): | Quality Assurance Project Plan. Sacramento and San Joaquin River Basins and Sacramento-San Joaquin Delta TMDL Monitoring for Organophosphorus Pesticides and Other Pesticides Identified as Posing a High Risk to Surface Waters. Final. SWAMP Project ID 02TM5001 (Revision 0.0). John Muir Institute of the Environment, U.C. Davis. Davis, CA. January 26, 2006

DECISION ID | 14391
Pollutant: | Oxyfluorfen
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Agriculture
Expected TMDL Completion Date: | 2021
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. 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 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 satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of 8 water samples exceed the oxyfluorfen Evaluation Guideline value of 0.29 (the 96-hour EC50 for Selenastrum capricornutum, a green algae), and this exceeds the narrative toxicity objective and, therefore, 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 be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 14391

LOE ID: | 26107
Pollutant: | Oxyfluorfen
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Eight water samples were collected from Gilsizer Slough from January to July 2006 for the Pesticide TMDL program. Two of the 8 samples had oxyfluorfen concentrations that exceeded the Evaluation Guideline of 0.29 ug/L.
Data Reference: | Zipped file of Central Valley Waterways Pesticide TMDL monitoring data spreadsheets and reports
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | Where valid testing has developed 96 hour LC50 values for aquatic organisms (the concentration that kills one half of the test organisms in 96 hours), the Board will consider one tenth of this value for the most sensitive species tested as the upper limit (daily maximum) for the protection of aquatic life. Other available technical information on the pesticide (such as Lowest Observed Effect Concentrations and No Observed Effect Levels), the water bodies and the organisms involved will be evaluated to determine if lower concentrations are required to meet the narrative objectives (CVRWQCB, 2007). The 96-hour EC50 value for oxyfluorfen for the most sensitive freshwater species tested (Green algae, Selenastrum capricornutum) is 0.29 ug/L.
Guideline Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
| Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs
Spatial Representation: | Water samples were collected from Gilsizer Slough at South Township Road.
Temporal Representation: | Water samples were collected daily during two storms in February 2006, and weekly in July 2006.
Environmental Conditions: |
QAPP Information: | Data Quality: Good. All sampling, analysis and QA/QC protocols are described in Calanchini (2006).
QAPP Information Reference(s):

DECISION ID | 9382
Pollutant: | pH
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for listing under sections 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Data is available from 1 line of evidence for this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollution combination on the section 303(d) list. The recommendation is based on staff findings that 7 of 15 available concentrations exceeded the water quality objective and this does exceed the allowable frequency using Table 3.2 of the Listing Policy. Table 3.2 of the listing policy recommends listing if a sample size of 15 has 5 or more samples that exceed the evaluation criteria. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 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 be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 9382

LOE ID: | 8794
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 15
Number of Exceedances: | 7
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Seven of the 15 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for pH. The exceeded results are as follows: 2/8/2001 - a sample taken at Gilsizer Slough @ O'banion Road had a result of 8.6-. 3/9/2001 - a sample taken at Gilsizer Slough @ O'banion Road had a result of 8.6-. 6/27/2001 - a sample taken at Gilsizer Slough @ O'banion Road had a result of 9.44-. 8/1/2001 - a sample taken at Gilsizer Slough @ O'banion Road had a result of 8.64-. 8/22/2001 - a sample taken at Gilsizer Slough @ O'banion Road had a result of 8.9-. 9/21/2001 - a sample taken at Gilsizer Slough @ O'banion Road had a result of 8.71-. 12/19/2001 - a sample taken at Gilsizer Slough @ O'banion Road had a result of 9.3-.
Data Reference: | SWAMP data entered by SWRCB into BDAT database
Water Quality Objective/Criterion: | pH levels should not be lower than 6.5 or higher than 8.5 (Basin Plan Objective)
Objective/Criterion Reference: | Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at Gilsizer Slough @ O'banion Road.
Temporal Representation: | The samples were collected from Dec 7 2000 to Jul 30 2002
Environmental Conditions: |
QAPP Information: | Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s):