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

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Butte Slough
Water Body ID: | CAR5203000020011128163228
Water Body Type: | River & Stream

DECISION ID | 4496
Pollutant: | Diazinon
Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not Delist from 303(d) list (TMDL required list)(2006)
Revision Status | Revised
Sources: | Agriculture
Expected TMDL Completion Date: | 2010
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for removal from the section 303(d) list under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess pollutant. None of 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 removing this water segment-pollutant combination from the section 303(d) list. 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 15 available 4-day average concentrations exceeded the 4-day average maximum concentration criterion and this is not a large enough sample size to make a determination according to Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are 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 removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 4496

LOE ID: | 21719
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Three water samples were collected from Butte Slough in February 2000, representing one calculated 4-day average concentration and three 1-hour maximum concentrations. Zero of one calculated 4-day average concentrations exceeded the 4-day maximum criterion of 0.10 ug/L. Zero of three 1-hour maximum concentrations exceeded the 1-hour maximum criterion of 0.16 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: | 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 Fish and Game Hazard Assessment diazinon freshwater aquatic life protection criteria of 0.160 ug/L (1-hour average) and 0.100 ug/L (4-day average) concentrations 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
| Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
Spatial Representation: | Samples were collected from Butte Slough at Pass Road.
Temporal Representation: | Samples were collected daily from 21 to 23 February, 2000.
Environmental Conditions: |
QAPP Information: | 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: | 21676
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 14
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Fourteen water samples were collected from Butte Slough between January 2005 and September 2006, representing fourteen calculated 4-day average concentrations and fourteen 1-hour maximum concentrations. Zero of fourteen calculated 4-day average concentrations exceeded the 4-day average criterion of 0.1 ug/L. Zero of fourteen 1-hour average concentrations exceeded the 1-hour average criterio of 0.16 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: | 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 Fish and Game Hazard Assessment diazinon freshwater aquatic life protection criteria: 0.160 ug/L (1-hour average) and 0.100 ug/L (4-day average) concentrations, 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
| Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game
Spatial Representation: | Samples were collected from Butte Slough at Pass Road.
Temporal Representation: | Samples were collected monthly from January 2005 through September 2006.
Environmental Conditions: |
QAPP Information: | 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: | 2674
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Not Specified
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 91
Number of Exceedances: | 20
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | There were 91 samples taken, 20 were in exceedance. All 20 exceedances were from the 1994 data. Some of the more recent data was "questionable" due to a possible bias (higher diazinon conc) from the ELISA method and as such could not be used in this assessment. When the chronic criteria could be applied, 4 out of 12 data set averages (4-day) exceeded the chronic criteria (Dileanis, 2002, Dileanis, 2002a, Dileanis, 2003b, Holmes et al., 2000).
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. Discharges shall not result in pesticide concentrations in bottom sediments or aquatic life that adversely affect beneficial uses. Total identifiable persistent chlorinated hydrocarbon pesticides shall not be present in the water column at concentrations detectable within the accuracy of analytical methods approved by the Environmental Protection Agency or the executive Officer. Waters designated for use as domestic or municipal supply (MUN) shall not contain concentrations of pesticides in excess of the Maximum Contaminant Levels set forth in California Code of Regulations, Title 22, Division 4, Chapter 15.
Objective/Criterion Reference: | Placeholder reference 2006 303(d)
Evaluation Guideline: | CDFG Hazard Assessment Criteria - 0.16 ug/L 1-hour average (acute), 0.10 ug/L 4-day average (chronic) (Siepman & Finlayson, 2000; Finlayson, 2004).
Guideline Reference: | Placeholder reference 2006 303(d)
Spatial Representation: | Samples were taken in Butte Slough at Lower Pass Road, Pass Road and Mawson Bridge near Colusa.
Temporal Representation: | Samples were collected in 1994 and from 2000 to 2002. There were no samples taken between 1994 and 2000.
Environmental Conditions: |
QAPP Information: | Data from USGS reports are considered of adequate quality per section 6.1.4 of the Policy.
QAPP Information Reference(s):

DECISION ID | 15006
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. 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 6 samples exceeded the E. Coli objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. According to table 3.2, a minimum sample size of 26 is required to designate a fully supporting use rating. 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 15006

LOE ID: | 21726
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 6
Number of Exceedances: | 1
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | The Sac Valley Water Quality Coalition collected 6 samples from March 2005 to October 2005. One of the 6 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 Butte Slough at Pass Road.
Temporal Representation: | Sampling occurred from March 2005 to October 2005.
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 | 15003
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 5 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 15003

LOE ID: | 21674
Pollutant: | Toxicity
LOE Subgroup: | Toxicity
Matrix: | Sediment
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: | TOXICITY TESTING
Data Used to Assess Water Quality: | 0/3 and 0/2 (0/5 total) samples, respectively, 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 Butte Slough at Lower Pass Road and at Pass Road
Temporal Representation: | Samples were collected from July 2005 - September 2006 and January 2005 - September 2005 respectively
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 | 15005
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: | 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 45 samples exceeded the pH 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 15005

LOE ID: | 21727
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 45
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | The Sacramento Valley Water Quality Coalition and the California Rice Commission collected 45 samples from September 2004 to September 2006. Two of the 45 samples did not meet the evaluation objective and had a pH lower than 6.5.
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: | The pH of water shall not be depressed below 6.5,raised above 8.5, or changed at any time more than 0.5 units from normal ambient pH. Measurement of pH within the range of 6.5 and 8.5. A low pH value is below 6.5.
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 Butte Slough at Lower Pass Road and Pass Road.
Temporal Representation: | Sampling occurred from September 2004 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 | 14227
Pollutant: | Dichlorvos
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 | Vector Control Sprays
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 water 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. Two of 7 water samples exceed the Evaluation Guideline (0.0085 ug/L, one-tenth the 96-hour LC50 for Daphnia magna, a freshwater invertebrate species) and, therefore, two samples exceeded the narrative toxicity objective, and 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 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 14227

LOE ID: | 26069
Pollutant: | Dichlorvos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 2
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Fourteen water samples were collected from Butte Slough, under the Irrigated Lands Regulatory Program, between January 2005 and September 2006. Seven of the 14 water samples had concentrations less than the quantitation limits (0.01 ug/L), which is greater than the water quality Evaluation Guideline value of 0.0085 ug/L and, therefore, could not be used for this assessment. Two of the 7 remaining usable water samples had concentrations that exceeded the Evaluation Guideline of 0.0085 ug/L.
Data Reference: | Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program
Water Quality Objective/Criterion: | 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).
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 96-hour LC50 value for the most sensitive freshwater species to dichlorvos (DDVP), based on toxicity to Daphnia magna (water flea, and invertebrate species) is 0.085 ug/L. The one-tenth of the LC50 value (0.0085 ug/L) is used as the Evaluation Guideline value for dichlorvos.
Guideline Reference: | Ecotox database, http://cfpub.epa.gov/ecotox/
Spatial Representation: | Water samples were collected from Butte Slough at Pass Road.
Temporal Representation: | Water samples were collected monthly between January 2005 and 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).
QAPP Information Reference(s):

DECISION ID | 12819
Pollutant: | Low Dissolved Oxygen
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 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. 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. Twenty-five of 45 water samples collected from Butte Slough exceed the Basin Plan minimum dissolved oxygen level for COLD and SPWN beneficial uses (7 mg/L), 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 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 12819

LOE ID: | 21725
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 45
Number of Exceedances: | 25
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Twenty-five of 45 water samples collected from Butte Slough between September 2004 and October 2006 exceed the Basin Plan minimum dissolved oxygen objective for COLD and SPWN (7 mg/L), and 6 of the 45 water samples also exceed the Basin Plan minimum dissolved oxygen objective for WARM beneficial uses (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: | The Basin Plan minimum dissolved oxygen objective for COLD and SPWN beneficial uses is 7 mg/l, and the Basin Plan minimum dissolved oxygen objective for WARM beneficial uses is 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: |
Temporal Representation: | Samples were collected between September 2004 and October 2006 at irregular intervals, including weekly, every two weeks, and monthly.
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 | 12747
Pollutant: | Unknown Toxicity
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 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. 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. Three of 26 water samples collected from Butte Slough exhibited a statistically significant decrease in Ceriodaphnia dubia (an invertebrate species) survival compared to control, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Two of 26 water samples collected from Butte Slough exhibited a statistically significant decrease in Pimephales promelas (a vertebrate species) survival compared to control, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 5.Twelve of 28 water samples collected from Butte Slough exhibited a statistically significant decrease in Selenastrum capricornutum (a plant species) growth (total cell counts) compared to control, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 6. 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 12747

LOE ID: | 21675
Pollutant: | Plant Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 28
Number of Exceedances: | 12
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Ten of 21 water samples collected from Butte Slough at Lower Pass Road, by the California Rice Commission under the Irrigated Lands Reporting Program, and tested for toxicity with Selenastrum capricornutum (an algal plant species), exhibited statistically significant differences in growth (total cell counts) compared to control samples and, therefore, exceeded the narrative toxicity objective. The ten water sample dates that exhibited toxicity, and their associated percent of control values, were collected on: 26 April 2005 (70%), 20 September 2005 (47%), 30 May 2006 (65%), 13 June 2006 (54%), 22 June 2006 (63%), 25 July 2006 (64%), 1 August 2006 (75%), 20 September 2006 (10%), 27 September 2006 (23%), and 25 October 2006 (77%). Two of 7 water samples collected from Butte Slough at Pass Road, by the Sac Valley Water Quality Coalition under the Irrigated Lands Reporting Program, and tested with Selenastrum capricornutum (an algal plant species), exhibited statistically significant differences in growth (total cell counts)compared to control samples and, therefore, exceeded the narrative toxicity objective. The toxic water samples were collected on 5 July 2005 (87% of control) and on 24 August 2005 (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 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: | Water samples were collected from Butte Slough at Lower Pass Road (by the California Rice Commission), and from Butte Slough at Pass Road (by the Sac Valley Water Quality Coalition).
Temporal Representation: | Water samples were collected monthly (with two 5-month gaps between October and March, and two samples per month in June, August, and September 2006) from Butte Slough at Lower Pass Road by the California Rice Commission, on 21 dates between 28 September 2004 and 25 October 2006. Water samples were also collected monthly or every two months (every two weeks in October 2005) from Butte Slough at Pass Road by the Sac Valley Water Quality Coalition, on 7 dates between 27 January 2005 and 18 October 2005.
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.
QAPP Information Reference(s):
LOE ID: | 21672
Pollutant: | Invertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 26
Number of Exceedances: | 3
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Two of 18 water samples collected from Butte Slough at Lower Pass Road, by the California Rice Commission under the Irrigated Lands Reporting Program, and tested for acute toxicity with Ceriodaphnia dubia (an invertebrate species), exhibited statistically significant differences (decreases) in survival compared to control samples and, therefore, exceeded the narrative toxicity objective. The two water sample dates that exhibited acute toxicity, and their associated mean percent survival rate and percent of control values, were collected on 18 October 2005, 0% mean survival (0% of control), and on 25 October 2006, 15% mean survival (15% of control). One of 8 water samples collected from Butte Slough at Pass Road, by the Sac Valley Water Quality Coalition under the Irrigated Lands Reporting Program, and tested for acute toxicity with Ceriodaphnia dubia (an invertebrate species), exhibited a statistically significant difference (decrease) in survival compared to control samples and, therefore, exceeded the narrative toxicity objective. The toxic water sample was collected on 18 October 2005, and had an associated mean percent survival rate of 0%, and percent of control of 0%.
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: | Water samples were collected from Butte Slough at Lower Pass Road (by the California Rice Commission), and from Butte Slough at Pass Road (by the Sac Valley Water Quality Coalition).
Temporal Representation: | Water samples were collected monthly (with two 5-month gaps between October and March) from Butte Slough at Lower Pass Road by the California Rice Commission, on 18 dates between 24 September 2004 and 25 October 2006. Water samples were also collected monthly or every two months (every two weeks in October 2005) from Butte Slough at Pass Road by the Sac Valley Water Quality Coalition, on 8 dates between 27 January 2005 and 21 October 2005.
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.
QAPP Information Reference(s):
LOE ID: | 21673
Pollutant: | Vertebrate Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 26
Number of Exceedances: | 2
Data and Information Type: | TOXICITY TESTING
Data Used to Assess Water Quality: | Two of 19 water samples collected from Butte Slough at Lower Pass Road, by the California Rice Commission under the Irrigated Lands Reporting Program, and tested for acute toxicity with Pimephales promelas (Fathead Minnow, a vertebrate species), exhibited statistically significant differences (decreases) in survival compared to control samples and, therefore, exceeded the narrative toxicity objective. The two water sample dates that exhibited acute toxicity, and their associated mean percent survival rate and percent of control values, were collected on 2 March 2005, 70% mean survival (74% of control), and on 13 June 2006, 75% mean survival (75% of control). Zero of 7 water samples collected from Butte Slough at Pass Road, by the Sac Valley Water Quality Coalition under the Irrigated Lands Reporting Program, and tested for acute toxicity with Pimephales promelas (Fathead Minnow, a vertebrate species), exhibited statistically significant differences in survival compared to control samples and, therefore, none exceeded the narrative toxicity 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. 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: | Water samples were collected from Butte Slough at Lower Pass Road (by the California Rice Commission), and from Butte Slough at Pass Road (by the Sac Valley Water Quality Coalition).
Temporal Representation: | Water samples were collected monthly (with two 5-month gaps between October and March, and two samples collected in June 2006) from Butte Slough at Lower Pass Road by the California Rice Commission, on 19 dates between 28 September 2004 and 25 October 2006. Water samples were also collected monthly or every two months from Butte Slough at Pass Road by the Sac Valley Water Quality Coalition, on 7 dates between 27 January 2005 and 18 October 2005.
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.
QAPP Information Reference(s):