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

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Cache Creek, Lower (Clear Lake Dam to Cache Creek Settling Basin near Yolo Bypass)
Water Body ID: | CAR5133202219980813161630
Water Body Type: | River & Stream

DECISION ID | 6661
Pollutant: | Mercury
Final Listing Decision: | Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (being addressed by USEPA approved TMDL)(2006)
Revision Status | Revised
Sources: | Resource Extraction
TMDL Name: | Cache Creek, Bear Creek, and Harley Gulch Mercury TMDL Project
TMDL Project Code: | 127
Date TMDL Approved by USEPA: | 02/07/2007
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | The Cache Creek, Bear Creek and Harley Gulch Mercury TMDL was approved by the RWQCB and subsequently approved by USEPA on 2/7/07. This water segment-pollutant combination is listed in the Water Quality Limited Segments Being Addressed portion of the section 303(d) list.
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: | After review of the available information for this recommendation, SWRCB staff conclude that the water body pollutant combination should be placed in the Water Quality Limited Segments Being Addressed category of the section 303(d) list because a TMDL has been approved.
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 6661

LOE ID: | 2592
Pollutant: | Mercury
LOE Subgroup: | Pollutant-Tissue
Matrix: | Tissue
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference 2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: |
Temporal Representation: |
Environmental Conditions: |
QAPP Information: | QA Info Missing
QAPP Information Reference(s):

DECISION ID | 14993
Pollutant: | DDD (Dichlorodiphenyldichloroethane)
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 4 samples exceeded the California Toxic Rule/USEPA (CTR/USEPA) criteria limit of 0.00083 μg/L for total DDT based on a human health carcinogenic risk level of 10-6 for consumption of water and aquatic organisms 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 14993

LOE ID: | 21733
Pollutant: | DDD (Dichlorodiphenyldichloroethane)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
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 Cache Creek between April 2004 and September 2004. None of the Four samples exceeded the California Toxic Rule/USEPA (CTR/USEPA) criteria limit of 0.00083 ug/L for DDD based on a human health carcinogenic risk level of 10-6 for consumption of water and aquatic organisms.- The Four samples had a high Reporting Limit hence the data could not be used in the analysis for exceedance (Listing Policy, Section 6.5.1.1) (SWRCB, 2004).
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
Water Quality Objective/Criterion: | - Sacramento/San Joaquin River Basin Plan (CVRWQCB, 2007) Pesticides: 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.- California Toxics Rule Criteria (USEPA, 2000)Inland Surface Waters based on drinking water and aquatic organism consumption. The criteria are based on human health protection for carcinogenicity at 1-in-a-million risk level (30-day average) with a limit of 0.00083 ug/L for DDD.
Objective/Criterion Reference: | Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
| 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 an input channel of Cache Creek in Yolo County.
Temporal Representation: | Samples were collected between November 2003 and September 2004 at irregular intervals on these dates 04/23, 6/26, 8/20 and 9/21.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):

DECISION ID | 14995
Pollutant: | DDE (Dichlorodiphenyldichloroethylene)
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 6 samples exceeded the California Toxic Rule/USEPA (CTR/USEPA) criteria limit of 0.00059 μg/L for DDE based on a human health carcinogenic risk level of 10-6 for consumption of water and aquatic organisms 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 14995

LOE ID: | 21734
Pollutant: | DDE (Dichlorodiphenyldichloroethylene)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
Number of Samples: | 6
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | - Six water samples (30-day average) were collected from Cache Creek between January 2003 and September 2004. None of the Six samples exceeded the California Toxic Rule/USEPA (CTR/USEPA) criteria limit of 0.00059 ug/L for DDE based on a human health carcinogenic risk level of 10-6 for consumption of water and aquatic organisms.- Four samples had a high Reporting Limit hence the data could not be used in the analysis for exceedance (Listing Policy, Section 6.5.1.1) (SWRCB, 2004).
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
Water Quality Objective/Criterion: | - Sacramento/San Joaquin River Basin Plan (CVRWQCB, 2007) Pesticides: 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.- California Toxics Rule Criteria (USEPA, 2000)Inland Surface Waters based on drinking water and aquatic organism consumption. The criteria are based on human health protection for carcinogenicity at 1-in-a-million risk level (30-day average) with a limit of 0.00059 ug/L for DDE.
Objective/Criterion Reference: | Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
| 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 an input channel of Cache Creek in Yolo County.
Temporal Representation: | Samples were collected between November 2003 and September 2004 at irregular intervals on these dates 04/23, 6/26, 8/20 and 9/21.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):

DECISION ID | 14997
Pollutant: | DDT (Dichlorodiphenyltrichloroethane)
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 California Toxic Rule/USEPA (CTR/USEPA) criteria limit of 0.00059 μg/L for DDT based on a human health carcinogenic risk level of 10-6 for consumption of water and aquatic organisms 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 14997

LOE ID: | 21735
Pollutant: | DDT (Dichlorodiphenyltrichloroethane)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Commercial or recreational collection of fish, shellfish, or organisms
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 Cache Creek between 2003 and 2004. None of the Five samples exceeded the California Toxic Rule/USEPA (CTR/USEPA) criteria limit of 0.00059 ug/L for total DDT based on a human health carcinogenic risk level of 10-6 for consumption of water and aquatic organisms.- Four samples had a high Reporting Limit hence the data could not be used in the analysis for exceedance (Listing Policy, Section 6.5.1.1) (SWRCB, 2004).
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
Water Quality Objective/Criterion: | - Sacramento/San Joaquin River Basin Plan (CVRWQCB, 2007) Pesticides: 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.- California Toxics Rule Criteria (USEPA, 2000)Inland Surface Waters based on drinking water and aquatic organism consumption. The criteria are based on human health protection for carcinogenicity at 1-in-a-million risk level (30-day average) with a limit of 0.00059 ug/L for DDT.
Objective/Criterion Reference: | Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
| 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 an input channel of Cache Creek in Yolo County.
Temporal Representation: | Samples were collected between November 2003 and September 2004 at irregular intervals on these dates 04/23, 6/26, 8/20 and 9/21.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):

DECISION ID | 15000
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. 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 12 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 15000

LOE ID: | 21736
Pollutant: | Escherichia coli (E. Coli)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 12
Number of Exceedances: | 4
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | The Yolo Bypass Watershed Planning Program collected 12 samples from November 2003 to October 2004. Four of the 12 samples exceeded the evaluation objective.
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
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
Evaluation Guideline: | In waters designated for contact recreation (REC-1), the E. coli concentration, based on a minimum of not less than five samples equally spaced over a 30-day period, shall not exceed a geometric mean of 126 MPN/100 mL and shall not exceed 235 MPN /100 mL in any single sample.
Guideline Reference: | Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002
Spatial Representation: | Samples were collected from Cache Creek.
Temporal Representation: | Sampling occurred from November 2003 to October 2004.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):

DECISION ID | 15001
Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | This pollutant is being considered for placement on the section 303(d) list under section 3.2 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 12 calculated geometric means exceeded the fecal coliform objective and this does not exceed theAccording to table 3.2, a minimum sample size of 26 is required to designate a fully supporting use rating. 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 15001

LOE ID: | 21737
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 12
Number of Exceedances: | 4
Data and Information Type: | PATHOGEN MONITORING
Data Used to Assess Water Quality: | The Yolo Bypass Watershed Planning Program collected 12 samples from November 2003 to October 2004. The geometric mean per month per site was calculated from the samples and 4 out of the 12 calculated geometric means exceeded the evaluation objective.
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
Water Quality Objective/Criterion: | In waters designated for contact recreation (REC-1), the fecal coliform concentration based on a minimum of not less than five samples for any 30-day period shall not exceed a geometric mean of 200/100 ml, nor shall more than ten percent of the total number of samples taken during any 30-day period exceed 400/100 ml.
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 Cache Creek.
Temporal Representation: | Sampling occurred from November 2003 to October 2004
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):

DECISION ID | 14990
Pollutant: | Selenium
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 6 samples exceeded the California Toxics Rule (CTR) criterion 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 14990

LOE ID: | 21732
Pollutant: | Selenium
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: | Water samples were collected on 6 occasions and analyzed for total recoverable and dissolved Se. The range of concentrations in total recoverable samples was 0.6-2 ?g/L. The range of concentrations in dissolved samples was 0.5-2??g/L.
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
Water Quality Objective/Criterion: | CTR criterion of 5 ug/L, total recoverable Se, for the protection of freshwater aquatic life (4-day average concentration to protect from extended period of exposure).
Objective/Criterion Reference: | Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency
| 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 within the Yolo Bypass, just downstream from the low flow outlet of the Cache Creek Settling Basin .
Temporal Representation: | Samples were collected on: 11/22/03, 1/23/04, 4/23/04, 6/26/04, 8/20/04, and 9/22/04.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):

DECISION ID | 14988
Pollutant: | Boron
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. Two lines of evidence are available in the administrative record to assess this pollutant. Five 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. Five of 6 samples exceed the water quality objective for total Boron and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. In addition, 5 of 6 samples exceed the water quality objective for dissolved Boron 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 14988

LOE ID: | 21730
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Agricultural Supply
Number of Samples: | 6
Number of Exceedances: | 5
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Five of 6 samples collected from Cache Creek between November 22 2003 and September 22 2004 contained total Boron at concentrations that exceeded the evaluation guideline for Boron.
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
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 (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: | Boron levels should not exceed the Agricultural Water Quality Goal for Boron of 700 ug/L (Ayers and Westcott, 1985).
Guideline Reference: | Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
Spatial Representation: | Samples were collected at the lower end of Cache Creek (Cache Creek outfall to Yolo Bypass).
Temporal Representation: | Samples were collected approximately bimonthly from November 22 2003 to September 22 2004. Cache Creek extends from Clear Lake southeastward to the Yolo Bypass.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):
LOE ID: | 21731
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Agricultural Supply
Number of Samples: | 6
Number of Exceedances: | 5
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Five of 6 samples collected from Cache Creek between November 22 2003 and September 22 2004 contained dissolved Boron at concentrations that exceeded the evaluation guideline for Boron.
Data Reference: | Yolo Bypass Water Quality Management Plan Report. Prepared under CALFED Watershed Grant, Agreement # 4600001691 for the City of Woodland
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 (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: | Boron levels should not exceed the Agricultural Water Quality Goal for Boron of 700 ug/L (Ayers and Westcott, 1985).
Guideline Reference: | Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)
Spatial Representation: | Samples were collected at the lower end of Cache Creek (Cache Creek outfall to Yolo Bypass).
Temporal Representation: | Samples were collected approximately bimonthly from November 22 2003 to September 22 2004. Cache Creek extends from Clear Lake southeastward to the Yolo Bypass.
Environmental Conditions: |
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with the Quality Assurance Project Plan For Water Quality Monitoring For The Yolo Bypass Watershed Planning Project, 2003-2004
QAPP Information Reference(s):

DECISION ID | 6629
Pollutant: | Unknown Toxicity
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2006)
Revision Status | Original
Sources: | Source Unknown
Expected TMDL Completion Date: | 2019
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | 303(d) listing decisions made prior to 2006 were not held in an assessment database. The Regional Boards will update this decision when new data and information become available and are assessed.
RWQCB Board Decision / Staff Recommendation: | No new data were assessed for 2008. The Regional Board will update this decision when new data and information become available and are assessed.
SWRCB Board Decision / Staff Recommendation: | N/A
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 6629

LOE ID: | 4290
Pollutant: | Unknown Toxicity
LOE Subgroup: | Toxicity
Matrix: | Water
Fraction: | Not Recorded
Beneficial Use: | Warm Freshwater Habitat
Number of Samples: | 0
Number of Exceedances: | 0
Data and Information Type: | Not Specified
Data Used to Assess Water Quality: | Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.
Data Reference: | Placeholder reference pre-2006 303(d)
Water Quality Objective/Criterion: |
Objective/Criterion Reference:
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Unspecified
Temporal Representation: | Unspecified
Environmental Conditions: | Unspecified
QAPP Information: | Unspecified
QAPP Information Reference(s):