Draft California 2024 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name:	Barker Slough (in Delta Waterways, northwestern portion)
Water Body ID:	CAR5100000020221031034216
Water Body Type:	River & Stream


DECISION ID	152076	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1, 1-dichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152076, 1, 1-dichloroethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309044

Pollutant:

1, 1-dichloroethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for 1, 1-Dichloroethane incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 5 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152079	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1, 2-Dibromoethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. 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. Zero of the zero 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. Zero of the zero samples exceed the water quality objective and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152079, 1, 2-Dibromoethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309047

Pollutant:

1, 2-Dibromoethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 77 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for ethylene dibromide (EDB) incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 0.05 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152131	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1, 3 -dichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152131, 1, 3 -dichlorobenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309112

Pollutant:

1, 3 -dichlorobenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Basin Plan).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 3-Dichlorobenzene criterion for the protection of human health from consumption of only organisms is 2,600 ug/L (California Toxics Rule, 2000).

Guideline 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

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152131, 1, 3 -dichlorobenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309113

Pollutant:

1, 3 -dichlorobenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 3-Dichlorobenzene criterion for the protection of human health from the consumption of water and organisms is 400 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152081	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1, 4 -dichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152081, 1, 4 -dichlorobenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309049

Pollutant:

1, 4 -dichlorobenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for 1, 4-Dichlorobenzene incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 5 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152081, 1, 4 -dichlorobenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309114

Pollutant:

1, 4 -dichlorobenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 4-Dichlorobenzene criterion for the protection of human health from consumption of only organisms is 2,600 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152075	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1,1,1-Trichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven 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 CWA 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 the seventy-seven samples exceed the water quality 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152075, 1,1,1-Trichloroethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309043

Pollutant:

1,1,1-Trichloroethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for 1, 1, 1-Trichloroethane incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 200 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152128	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1,1,2-Trichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152128, 1,1,2-Trichloroethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309105

Pollutant:

1,1,2-Trichloroethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 1, 2-Trichloroethane criterion for the protection of human health from consumption of only organisms is 42 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152128, 1,1,2-Trichloroethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309106

Pollutant:

1,1,2-Trichloroethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 1, 2-Trichloroethane criterion for the protection of human health from consumption of water and organisms is 0.60 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152077	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1,2,4-Trichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven 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 CWA 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 the seventy-seven samples exceed the water quality 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152077, 1,2,4-Trichlorobenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309045

Pollutant:

1,2,4-Trichlorobenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: At a minimum, water designated for MUN shall not contain concentrations of chemical constituents in excess of the MCL specified in Title 22 of the California Code of Regulations. The MCL for 1,2,4-trichlorobenzene is 0.005 mg/L.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152129	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1,2-Dichloroethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the zero samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the zero samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152129, 1,2-Dichloroethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309109

Pollutant:

1,2-Dichloroethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 77 samples were analyzed, 0 of 0 samples exceed the criterion for 1, 2-Dichloroethane. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 2-Dichloroethane criterion for the protection of human health from the consumption of water and organisms is 0.38 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152129, 1,2-Dichloroethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309108

Pollutant:

1,2-Dichloroethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 2-Dichloroethane criterion for the protection of human health from consumption of only organisms is 99 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152130	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1,2-Dichloropropane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152130, 1,2-Dichloropropane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309110

Pollutant:

1,2-Dichloropropane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 2-Dichloropropane criterion for the protection of human health from consumption of only organisms is 39 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152130, 1,2-Dichloropropane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309111

Pollutant:

1,2-Dichloropropane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 2-Dichloropropane criterion for the protection of human health from the consumption of water and organisms is 0.52 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152083	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	2, 4 DB / 4-(2,4-dichlorophenoxy) butyric acid
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152083, 2, 4 DB / 4-(2,4-dichlorophenoxy) butyric acid	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309052

Pollutant:

2, 4 DB / 4-(2,4-dichlorophenoxy) butyric acid

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for 2,4-DB, 530 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for 2,4-DB is 5,300 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152084	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	2,4,5-TP (Silvex)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 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 CWA 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 19 samples exceed the water quality 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152084, 2,4,5-TP (Silvex)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309053

Pollutant:

2,4,5-TP (Silvex)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for 2, 4, 5-TP (Silvex) incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 50 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152082	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	2,4-D (2,4-Dichlorophenoxy acetic acid)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the Cold Freshwater Habitat evaluation guideline and zero of 19 samples exceed the Municipal & Domestic Supply 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 CWA 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 19 samples exceed the Cold Freshwater Habitat evaluation guideline and zero of 19 samples exceed the Municipal & Domestic Supply water quality objective. 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152082, 2,4-D (2,4-Dichlorophenoxy acetic acid)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309050

Pollutant:

2,4-D (2,4-Dichlorophenoxy acetic acid)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The EC50 for 2,4-D is 695 ug/l (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152082, 2,4-D (2,4-Dichlorophenoxy acetic acid)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309051

Pollutant:

2,4-D (2,4-Dichlorophenoxy acetic acid)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for 2, 4-D incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 70 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152109	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	2-Methyl-4-chlorophenoxyacetic acid (MCPA):acetic acid
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the evaluation guideline. 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 CWA 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 19 samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152109, 2-Methyl-4-chlorophenoxyacetic acid (MCPA):acetic acid	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309083

Pollutant:

2-Methyl-4-chlorophenoxyacetic acid (MCPA):acetic acid

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for MCPA, 9,100 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for MCPA is 91,000 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152085	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Alachlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the water quality objective for MUN, and zero of the nineteen samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the water quality objective for MUN, and zero of the nineteen samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152085, Alachlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309055

Pollutant:

Alachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for alachlor incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 2 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152085, Alachlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309054

Pollutant:

Alachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

According to the USEPA Office of Pesticide Programs Ecotoxicity database, the aquatic life EC50 for Alachlor is 1.64 ug/L.

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152086	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Aldicarb
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152086, Aldicarb	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309115

Pollutant:

Aldicarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Department of Public Health archived advisory level for aldicarb is 7 ug/L.

Guideline Reference:

CDPH Archived Advisory Levels for Drinking Water. Archived Advisory Levels are currently considered Notification Levels.

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152086, Aldicarb	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309056

Pollutant:

Aldicarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for aldicarb, 6.33 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for aldicarb is 63.3 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152132	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Aldicarb sulfoxide
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152132, Aldicarb sulfoxide	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309116

Pollutant:

Aldicarb sulfoxide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The USEPA drinking water standard (primary MCL) for aldicarb sulfoxide is 4 ug/L

Guideline Reference:

Aldicarb and Aldicarb Metabolites Technical Report.

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152133	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Aldrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of nineteen samples exceed the evaluation guideline for COLD, and 0 of 0 samples exceed the evaluation guideline for COMM, and 0 of 0 samples exceed the evaluation guideline for MUN. 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 CWA 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 nineteen samples exceed the evaluation guideline for COLD, and 0 of 0 samples exceed the evaluation guideline for COMM, and 0 of 0 samples exceed the evaluation guideline for MUN 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152133, Aldrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309117

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 19 samples were analyzed, 0 of 0 samples exceed the criterion for Aldrin. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Aldrin criterion for the protection of human health from consumption of only organisms is 0.00014 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152133, Aldrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309119

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 21 samples were analyzed, 0 of 0 samples exceed the criterion for Aldrin. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Aldrin criterion for the protection of human health from the consumption of water and organisms is 0.00013 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152133, Aldrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309118

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The aldrin criterion maximum concentration to protect aquatic life in freshwater is 1.5 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152087	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Atrazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). LOE 79720 has been replaced by LOE 221722 due to a reassessment of data using a U.S. EPA aquatic life benchmark. The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152087, Atrazine	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309157

Pollutant:

Atrazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Atrazine.

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins; Fifth Edition. Revised May 2018 (with approved amendments)

Evaluation Guideline:

The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of <1 ug/L for a nonvascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2008-09-17 and 2008-09-17

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.

Line of Evidence (LOE) for Decision ID 152087, Atrazine	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309057

Pollutant:

Atrazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for atrazine incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 1 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152088	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Azinphos-methyl (Guthion)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. 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. Zero of the zero samples exceed the evaluation guideline for COLD. 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 the zero samples exceed the evaluation guideline for COLD and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152088, Azinphos-methyl (Guthion)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309058

Pollutant:

Azinphos-methyl (Guthion)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 19 samples were analyzed, 0 of 0 samples exceed the criterion for Azinphos methyl. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The National Recommended Water Quality Criteria for Azinphos Methyl (Guthion) for the protection of freshwater aquatic life is a maximum of 0.01 ug/l.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152089	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Benefin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152089, Benefin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309059

Pollutant:

Benefin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

According to the USEPA Office of Pesticide Programs Ecotoxicity database, the freshwater aquatic life MATC for benfluralin is 3 ug/L.

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152090	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Benzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152090, Benzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309120

Pollutant:

Benzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Benzene criterion for the protection of human health from consumption of only organisms is 71 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152090, Benzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309060

Pollutant:

Benzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Benzene incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 1 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152147	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Bromacil
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available. LOE 79725 has been replaced by LOE 221468 due to a reassessment of data using a U.S. EPA aquatic life benchmark.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152147, Bromacil	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309155

Pollutant:

Bromacil

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Bromacil is the USEPA Aquatic Life Benchmark of 6.8 ug/L for a nonvascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2007-03-21 and 2007-03-21

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152134	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Bromoform
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152134, Bromoform	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309121

Pollutant:

Bromoform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Bromoform criterion for the protection of human health from consumption of only organisms is 360 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152134, Bromoform	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309122

Pollutant:

Bromoform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Bromoform criterion for the protection of human health from the consumption of water and organisms is 4.3 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152092	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Carbofuran
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the water quality objective for MUN, and zero of the zero samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the water quality objective for MUN, and zero of the zero samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152092, Carbofuran	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309063

Pollutant:

Carbofuran

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Carbofuran incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 18 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152092, Carbofuran	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309062

Pollutant:

Carbofuran

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 19 samples were analyzed, 0 of 0 samples exceed the criterion for Carbofuran. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The freshwater criterion maximum concentration for carbofuran is 0.5 µg/L (DFG 00-6, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152135	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Carbon tetrachloride
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the zero samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the zero samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152135, Carbon tetrachloride	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309123

Pollutant:

Carbon tetrachloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Carbon tetrachloride criterion for the protection of human health from consumption of only organisms is 4.4 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152135, Carbon tetrachloride	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309124

Pollutant:

Carbon tetrachloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The carbon tetrachloride criterion for the protection of human health from the consumption of water and organisms is 0.25 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152093	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Chlorobenzene (mono)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152093, Chlorobenzene (mono)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309064

Pollutant:

Chlorobenzene (mono)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for monochlorobenzene incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 70 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152093, Chlorobenzene (mono)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309125

Pollutant:

Chlorobenzene (mono)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Chlorobenzene criterion for the protection of human health from consumption of only organisms is 21,000 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152101	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Chlorodibromomethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152101, Chlorodibromomethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309073

Pollutant:

Chlorodibromomethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for total trihalomethanes incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 80 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152094	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Chloroform
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152094, Chloroform	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309066

Pollutant:

Chloroform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152094, Chloroform	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309065

Pollutant:

Chloroform

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: Waters shall not contain chemical constituents in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The National Recommended Water Quality Criterion for Chloroform for the protection of human health from consumption of organisms only is 2,000 ug/l.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152095	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Chlorpyrifos
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the evaluation guideline for COLD. 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 CWA 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 19 samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152095, Chlorpyrifos	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309067

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (Siepmann and Finlayson 2000).

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:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152098	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Cyanazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152098, Cyanazine	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309070

Pollutant:

Cyanazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The EC50 for cyanazine is 4.8 (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152099	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Demeton
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152099, Demeton	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309071

Pollutant:

Demeton

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The USEPA Recommended freshwater eaquatic life criteria for demeton is 0.1 ug/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152100	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Diazinon
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the evaluation guideline for COLD. 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 CWA 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 19 samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152100, Diazinon	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309072

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).

Guideline Reference:

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:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152091	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Dichlorobromomethane
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152091, Dichlorobromomethane	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309061

Pollutant:

Dichlorobromomethane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152102	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Dichloroprop
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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 available in the administrative record to assess this pollutant. Zero of the nineteen samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152102, Dichloroprop	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309074

Pollutant:

Dichloroprop

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

The evaluation guideline for dichlorprop, 270 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for dichlorprop is 2,700 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152103	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Dicofol
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152103, Dicofol	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309075

Pollutant:

Dicofol

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

According to the USEPA Office of Pesticide Programs Ecotoxicity database, the freshwater aquatic life MATC for dicofol is 5.9 ug/L.

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152136	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Dieldrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of nineteen samples exceed the evaluation guideline for COLD, and zero of zero samples exceed the evaluation guideline for COMM, and zero of zero samples exceed the evaluation guideline for MUN. 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 CWA 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 the nineteen samples exceed the evaluation guideline for COLD, and zero of the zero samples exceed the evaluation guideline for COMM and MUN 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152136, Dieldrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309126

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Nuisance

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 19 samples were analyzed, 0 of 0 samples exceed the criterion for Dieldrin. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Dieldrin criterion for the protection of human health from consumption of only organisms is 0.00014 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152136, Dieldrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309128

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 19 samples were analyzed, 0 of 0 samples exceed the criterion for Dieldrin. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Dieldrin criterion for the protection of human health from the consumption of water and organisms is 0.00014 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152136, Dieldrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309127

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152148	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Dimethoate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152148, Dimethoate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309156

Pollutant:

Dimethoate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for a invertebrate (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2006-06-21 and 2006-06-21

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152104	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Dinoseb
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the water quality objective for MUN, and zero of the nineteen samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the water quality objective for MUN, and zero of the nineteen samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152104, Dinoseb	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309076

Pollutant:

Dinoseb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for dinoseb, 4.4 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for dinoseb is 44 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152104, Dinoseb	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309077

Pollutant:

Dinoseb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Dinoseb incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 7 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152105	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Disulfoton
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. 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. Zero of the zero samples exceed the evaluation guideline. 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 the zero samples exceed the evaluation guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152105, Disulfoton	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309078

Pollutant:

Disulfoton

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The USEPA national ambient water quality criteria for freshwater aquatic life instantaneous maximum for disulfoton is 0.05 µg/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152139	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Endosulfan sulfate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline for MUN, zero of the nineteen samples exceed the evaluation guideline for COLD, and zero of the nineteen samples exceed the evaluation guideline for COMM. 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 CWA 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 the nineteen samples exceed the evaluation guideline for MUN, zero of the nineteen samples exceed the evaluation guideline for COLD, and zero of the nineteen samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152139, Endosulfan sulfate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309136

Pollutant:

Endosulfan sulfate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The USEPA National Recommended Water Quality Criterion to protect freshwater aquatic life from acute (24-Hour average) exposure to Endosulfan sulfate is 0.056 ug/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152139, Endosulfan sulfate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309135

Pollutant:

Endosulfan sulfate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endosulfan Sulfate criterion for the protection of human health from consumption of only organisms is 240 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152139, Endosulfan sulfate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309137

Pollutant:

Endosulfan sulfate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endosulfan Sulfate criterion to protect human health for waters that include the designated use of MUN is 110 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152140	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Endrin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline for MUN, zero of the nineteen samples exceed the evaluation guideline for COMM, and zero of the ten samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the evaluation guideline for MUN, zero of the nineteen samples exceed the evaluation guideline for COMM, and zero of the ten samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152140, Endrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309140

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endrin criterion for the protection of human health from the consumption of water and organisms is 0.76 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152140, Endrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309139

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

"Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. 0 of 10 samples exceed the COLD criterion for Endrin.
A total of 19 samples were analyzed. The sample results for nine samples were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. ""When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."""

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152140, Endrin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309138

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endrin criterion for the protection of human health from consumption only of organisms is 0.81 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152141	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Endrin aldehyde
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152141, Endrin aldehyde	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309141

Pollutant:

Endrin aldehyde

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endrin Aldehyde criterion for the protection of human health from consumption of only organisms is 0.81 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152146	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Esfenvalerate/Fenvalerate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152146, Esfenvalerate/Fenvalerate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309154

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Evaluation Guideline:

The chronic concentration goal for Esfenvalerate is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Esfenvalerate were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used. The evaluation guideline for fenvalerate, 0.113 ug/L, is one-tenth of the median lethal concentration (LC50 = 1.13 ug/L) as determined in a 96 hour toxicity test using the fathead minnow, Pimephales promelas. (USEPA OPP Ecotoxicity database)

Guideline Reference:

OPP Pesticide Ecotoxicity Database.

Guideline Reference:

Water Quality Criteria Report for Esfenvalerate

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152106	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Ethylbenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152106, Ethylbenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309142

Pollutant:

Ethylbenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Ethylbenzene criterion for the protection of human health from consumption of only organisms is 29,000 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152106, Ethylbenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309079

Pollutant:

Ethylbenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Ethylbenzene incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 300 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152107	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Glyphosate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152107, Glyphosate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309080

Pollutant:

Glyphosate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for glyphosate, 5500 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for glyphosate is 55000 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152107, Glyphosate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309081

Pollutant:

Glyphosate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Glyphosate incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 700 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152142	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Heptachlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.11 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. Zero of zero samples exceed the evaluation guideline for MUN, and zero of zero samples exceed the evaluation guideline for COMM, and zero of zero samples exceed the evaluation guideline for COLD. 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 CWA 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. Zero of zero samples exceed the evaluation guideline for MUN, and zero of zero samples exceed the evaluation guideline for COMM, and zero of zero samples exceed the evaluation guideline for COLD and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152142, Heptachlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309143

Pollutant:

Heptachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. However, because the sample results were below the method detection limit they could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Heptachlor criterion for the protection of human health from consumption of only organisms is 0.00021 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152142, Heptachlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309145

Pollutant:

Heptachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. However, because the sample results were below the method detection limit they could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Heptachlor criterion for the protection of human health from the consumption of water and organisms is 0.00021 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152142, Heptachlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309144

Pollutant:

Heptachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: Although a total of 21 samples were analyzed, 0 of 0 samples exceed the criterion for Heptachlor. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Heptachlor criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0019 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152143	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Heptachlor epoxide
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.11 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. Zero of the zero samples exceed the evaluation guideline for MUN, zero of the zero samples exceed the evaluation guideline for COLD and zero of the zero samples exceed the evaluation guideline for COMM. 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 CWA 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. Zero of the zero samples exceed the evaluation guideline for MUN, zero of the zero samples exceed the evaluation guideline for COLD and zero of the zero samples exceed the evaluation guideline for COMM and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152143, Heptachlor epoxide	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309148

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. 0 of 0 samples exceed the criterion for Heptachlor epoxide. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Heptachlor Epoxide criterion for the protection of human health from the consumption of water and organisms is 0.00010 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152143, Heptachlor epoxide	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309146

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. 0 of 0 samples exceed the criterion for Heptachlor epoxide. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Heptachlor Epoxide criterion for the protection of human health from consumption of only organisms is 0.00011 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152143, Heptachlor epoxide	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309147

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. 0 of 0 samples exceed the criterion for Heptachlor epoxide. The sample results were below the method detection limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Heptachlor Epoxide criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0038 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152144	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Hexachlorobutadiene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA 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. Zero of the zero samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the zero samples exceed the evaluation guideline for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152144, Hexachlorobutadiene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309150

Pollutant:

Hexachlorobutadiene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Hexachlorobutadiene criterion for the protection of human health from the consumption of water and organisms is 0.44 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152144, Hexachlorobutadiene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309149

Pollutant:

Hexachlorobutadiene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Hexachlorobutadiene criterion for the protection of human health from consumption of only organisms is 50 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152108	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Malathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the Cold Freshwater Habitat evaluation guideline. 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 CWA 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 19 samples exceed the Cold Freshwater Habitat evaluation guideline. 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152108, Malathion	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309082

Pollutant:

Malathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Aquatic life should not be affected unacceptably if the 4-day average concentration of malathion does not exceed 0.0002 ug/L (UC Davis Aquatic Life Criteria).

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152110	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Methidathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152110, Methidathion	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309084

Pollutant:

Methidathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

According to the USEPA Office of Pesticide Programs Ecotoxicity database, the freshwater aquatic life MATC for methidathion is 0.86 ug/L.

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152111	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Methiocarb
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152111, Methiocarb	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309085

Pollutant:

Methiocarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for methiocarb, 43.6 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for methiocarb is 436 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152112	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Methomyl
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. 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. Zero of the zero 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. Zero of zero samples exceeded the evaluation guideline and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152112, Methomyl	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309086

Pollutant:

Methomyl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The criteria for freshwater aquatic life for methomyl is 0.5 µg/L (Finlayson, 2004).

Guideline Reference:

Hazard Assessment of the Insecticide Methomyl to Aquatic Organisms in the San Joaquin River System - Administrative Report 96-6

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152113	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Methoxychlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline for MUN, and zero of the zero samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the evaluation guideline for MUN, and zero of the zero samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152113, Methoxychlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309087

Pollutant:

Methoxychlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The USEPA national ambient water quality criterion for freshwater aquatic life instantaneous maximum for methoxychlor is 0.03 µg/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152113, Methoxychlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309088

Pollutant:

Methoxychlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Methoxychlor incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 30 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152119	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Methyl Parathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152119, Methyl Parathion	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309095

Pollutant:

Methyl Parathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The USEPA National Recommended Water Quality maximum instantaneous criterion for freshwater aquatic life protection from acute exposure to Methyl Parathion is 0.08 ug/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152114	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Metolachlor
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152114, Metolachlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309089

Pollutant:

Metolachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The National Ambient Water Quality Criteria, Human Health and Welfare Protection, Public Health Effects (other than cancer effects) Water & Fish Consumption for metolachlor is 44 µg/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152114, Metolachlor	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309158

Pollutant:

Metolachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Metolachlor.

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Metolachlor is the USEPA Aquatic Life Benchmark of 1 ug/L for an invertebrate (chronic).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2005-06-15 and 2010-06-16

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152115	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Molinate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152115, Molinate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309091

Pollutant:

Molinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Molinate incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 20 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152115, Molinate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309090

Pollutant:

Molinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

According to the USEPA Office of Pesticide Programs Ecotoxicity database, the freshwater aquatic life MATC for molinate is 600 ug/L.

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152115, Molinate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309159

Pollutant:

Molinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The California Department of Fish and Wildlife hazard assessment instantaneous criterion (1-hour average) for the protection of aquatic life for Molinate is 13 ug/L.

Guideline Reference:

Hazard Assessment of the Rice Herbicides Molinate and Thiobencarb to Aquatic Organisms in the Sacramento River System. Administrative Report 90-1. California Department of Fish and Game, Environmental Services Division

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2004-06-15 and 2004-06-15

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152116	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Napropamide
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152116, Napropamide	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309092

Pollutant:

Napropamide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for napropamide, 1,200 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for napropamide is 12,000 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152149	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Norflurazon
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152149, Norflurazon	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309161

Pollutant:

Norflurazon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Norflurazon is the USEPA Aquatic Life Benchmark of 9.7 ug/L for a nonvascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2007-03-21 and 2007-03-21

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152117	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Oxyfluorfen
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the evaluation guideline. 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 CWA 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 19 samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152117, Oxyfluorfen	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309093

Pollutant:

Oxyfluorfen

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for oxyfluorfen, 20 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for oxyfluorfen is 200 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152118	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Parathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152118, Parathion	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309094

Pollutant:

Parathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The USEPA recommended freshwater aquatic life criteria (chronic) for parathion ethyl is 0.013 µg/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152120	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Pendimethalin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the Cold Freshwater Habitat evaluation guideline. 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 CWA 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 19 samples exceed the Cold Freshwater Habitat evaluation guideline. 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152120, Pendimethalin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309096

Pollutant:

Pendimethalin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for pendimethalin is the EC50 5.4 ug/L. (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152121	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Phorate
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152121, Phorate	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309097

Pollutant:

Phorate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for phorate, 0.2 ug/L, is one-tenth of the median lethal concentration (LC50). The LC50 for phorate is 2 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152122	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Phosmet
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152122, Phosmet	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309098

Pollutant:

Phosmet

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The evaluation guideline for phosmet is the EC50 5.6 ug/L. (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152123	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Prometryn
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152123, Prometryn	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309099

Pollutant:

Prometryn

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The EC50 for prometryn is 1 ug/l (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152124	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Propargite
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the evaluation guideline. 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 CWA 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 the nineteen samples exceed the evaluation guideline 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152124, Propargite	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309100

Pollutant:

Propargite

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

According to the USEPA Office of Pesticide Programs Ecotoxicity database, the freshwater aquatic life MATC for propargite is 11 ug/L.

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152125	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Simazine
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicants (Table 3.1 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152125, Simazine	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309101

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Simazine incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 4 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152125, Simazine	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309160

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Simazine.

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Simazine is the USEPA Aquatic Life Benchmark of 6 ug/L for a nonvascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2005-03-16 and 2010-03-17

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152097	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Specific Conductivity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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 available in the administrative record to assess this pollutant. Zero of the seventy-seven 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 CWA 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. Zero of the seventy-seven samples exceed the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152097, Specific Conductivity	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309069

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference in the Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin for specific conductance is 900 uS/cm.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152126	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Thiobencarb
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the nineteen samples exceed the water quality objective for MUN, and zero of the nineteen samples exceed the evaluation guideline for COLD. 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 CWA 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 the nineteen samples exceed the water quality objective for MUN, and zero of the nineteen samples exceed the evaluation guideline for COLD 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152126, Thiobencarb	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309102

Pollutant:

Thiobencarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

According to the USEPA Office of Pesticide Programs Ecotoxicity database, the freshwater aquatic life MATC for Thiobencarb is 1.4 ug/L.

Guideline Reference:

Ecotoxicity database. U.S. Environmental Protection Agency, Office of Pesticide Programs

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152126, Thiobencarb	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309103

Pollutant:

Thiobencarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The site specific objective for thiobencarb for the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 1 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152127	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Toluene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152127, Toluene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309104

Pollutant:

Toluene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for Toluene incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 150 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152127, Toluene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309151

Pollutant:

Toluene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Toluene criterion for the protection of human health from consumption of only organisms is 200,000 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152073	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Total Dissolved Solids
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2024)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Zero samples exceeded the objectives, guidelines, or criteria for beneficial uses applicable to this water segment-pollutant combination, which is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for conventional or other pollutants (Table 3.2 of the Listing Policy). The data used satisfies the data quality requirements (section 6.1.4) and data quantity requirements (section 6.1.5) of the Listing Policy. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. 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 CWA section 303(d) List.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152073, Total Dissolved Solids	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309041

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

None of the 77 samples were over 500 mg/L.

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The secondary MCLs for Total Dissolved Solids provide a range of values including a recommended level (500 mg/L), upper level (1000 mg/L) and a short-term level (1500 mg/L). The 'recommended' concentration of 500 mg/L was used as it is intended to be protective of all drinking water uses.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Objective/Criterion Reference:

Secondary Maximum Contaminant Levels and Compliance. CCR Title 22 section 64449.

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples collected from the KG000000 station.

Temporal Representation:

Samples were collected approximately once a month from January 2004 to June 2010.

Environmental Conditions:

QAPP Information:

N/A

QAPP Information Reference(s):


DECISION ID	152145	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Toxaphene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.11 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. Zero of the zero samples exceed the evaluation guideline for MUN, and zero of the zero samples exceed the evaluation guideline for COLD. 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 CWA 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. Zero of the zero samples exceed the evaluation guideline for MUN, and zero of the zero samples exceed the evaluation guideline for COLD and this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples are needed to determine if a beneficial use is fully supported using table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152145, Toxaphene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309152

Pollutant:

Toxaphene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Toxaphene criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0002 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152145, Toxaphene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309153

Pollutant:

Toxaphene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 5 - Central Valley Region staff assessed DWR data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support. A total of 19 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Toxaphene criterion for the protection of human health from the consumption of water and organisms is 0.00073 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152150	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Triclopyr
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152150, Triclopyr	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309162

Pollutant:

Triclopyr

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Triclopyr is the USEPA Aquatic Life Benchmark of 26 ug/L for a fish (chronic) for Triclopyr Butoxyethyl Ester (BEE).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2006-09-20 and 2006-09-20

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152151	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Trifluralin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152151, Trifluralin	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309163

Pollutant:

Trifluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Trifluralin is the USEPA Aquatic Life Benchmark of 1.9 ug/L for a fish (chronic).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (KG000000)

Temporal Representation:

The samples were collected between the dates of 2004-06-15 and 2004-06-15

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Quality Assurance Project Plan from Bryte Chemical Laboratory.


DECISION ID	152074	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Turbidity
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. One of the 77 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 CWA 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. One of 77 samples exceeded the 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152074, Turbidity	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309042

Pollutant:

Turbidity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

One of the 77 samples exceeded the objective.

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Sacramento/San Joaquin Basin Plan (2011): For Delta waters, the general objectives for turbidity apply subject to the following: except for periods of storm runoff, the turbidity of Delta waters shall not exceed 50 NTUs in the waters of the Central Delta and 150 NTUs in other Delta waters. The 150 NTU objective was used to assess the data for this water body.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the KG000000 station.

Temporal Representation:

Samples were collected approximately once a month from January 2004 to June 2010.

Environmental Conditions:

QAPP Information:

N/A

QAPP Information Reference(s):


DECISION ID	152137	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	alpha-Endosulfan (Endosulfan 1)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the Cold Freshwater Habitat evaluation guideline, zero of 19 samples exceed the Commercial or recreational collection of fish, shellfish, or organisms evaluation guideline, and zero of 19 samples exceed the Municipal & Domestic Supply evaluation guideline. 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 CWA 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 19 samples exceed the Cold Freshwater Habitat evaluation guideline, zero of 19 samples exceed the Commercial or recreational collection of fish, shellfish, or organisms evaluation guideline, and zero of 19 samples exceed the Municipal & Domestic Supply evaluation guideline. 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152137, alpha-Endosulfan (Endosulfan 1)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309129

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endosulfan I criterion for the protection of human health from consumption of only organisms is 240 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152137, alpha-Endosulfan (Endosulfan 1)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309130

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The endosulfan I criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152137, alpha-Endosulfan (Endosulfan 1)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309131

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

California Toxics Rule criteria for alpha-endosulfan to protect human health for waters that include the designated use of MUN is 110 ug/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152138	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	beta-Endosulfan (Endosulfan 2)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of 19 samples exceed the Cold Freshwater Habitat evaluation guideline, zero of 19 samples exceed the Commercial or recreational collection of fish, shellfish, or organisms evaluation guideline, and zero of 19 samples exceed the Municipal & Domestic Supply evaluation guideline. 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 CWA 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 19 samples exceed the Cold Freshwater Habitat evaluation guideline, zero of 19 samples exceed the Commercial or recreational collection of fish, shellfish, or organisms evaluation guideline, and zero of 19 samples exceed the Municipal & Domestic Supply evaluation guideline. 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152138, beta-Endosulfan (Endosulfan 2)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309134

Pollutant:

beta-Endosulfan (Endosulfan 2)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

California Toxics Rule criteria for beta-endosulfan to protect human health for waters that include the designated use of MUN is 110 ug/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152138, beta-Endosulfan (Endosulfan 2)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309133

Pollutant:

beta-Endosulfan (Endosulfan 2)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The endosulfan II criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.028 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152138, beta-Endosulfan (Endosulfan 2)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309132

Pollutant:

beta-Endosulfan (Endosulfan 2)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The Endosulfan II criterion for the protection of human health from consumption of only organisms is 240 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 6/15/2004 10:08:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152096	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	cis-1,2-Dichloroethylene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the water quality objective for MUN. 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 CWA 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 the seventy-seven samples exceed the water quality objective for MUN 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152096, cis-1,2-Dichloroethylene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309068

Pollutant:

cis-1,2-Dichloroethylene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for cis-1,2-Dichloroethylene incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 6 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):


DECISION ID	152080	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	o-Dichlorobenzene
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. Zero of the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM. 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 CWA 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 the seventy-seven samples exceed the water quality objective for MUN, and zero of the seventy-seven samples exceed the evaluation guideline for COMM 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152080, o-Dichlorobenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309048

Pollutant:

o-Dichlorobenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for 1, 2-Dichlorobenzene incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 600 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152080, o-Dichlorobenzene	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309107

Pollutant:

o-Dichlorobenzene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

The 1, 2-Dichlorobenzene criterion for the protection of human health from consumption of only organisms is 17,000 ug/L (California Toxics Rule, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

Quality Assurance Project Plan for Bryte Chemical Laboratory

QAPP Information Reference(s):


DECISION ID	152072	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2024)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was split as part of the 2024 cycle Delta Remapping Project. Decisions were reassessed based on the new spatial representation. This pollutant is being considered for placement on the CWA 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. One of 77 samples, reported as the dissolved fraction exceeds the objective for Cold Freshwater Habitat. 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 CWA 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. One of 77 samples, reported as the dissolved fraction exceeds the objective for Cold Freshwater Habitat 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.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 152072, pH	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309040

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Numeric data generated from 77 samples collected had 1 exceedence.

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH shall not be depressed below 6.5 nor raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the KG000000 station.

Temporal Representation:

Samples were collected approximately once a month from January 2004 to June 2010.

Environmental Conditions:

QAPP Information:

N/A

QAPP Information Reference(s):


DECISION ID	153974	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	Aluminum
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	During 2024 cycle, the 1988 National Recommended Water Quality Criteria used to assess aluminum data was replaced with U.S. EPA’s 2018 Final Recommended Aquatic Life Criteria for Aluminum in Freshwater. This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.11 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. 15 of 52 samples (total) and zero 0f 3 samples (dissolved) exceed the criteria for COLD. These sampling locations did not have site specific pH data associated with them to complete the calculation of the aluminum criteria. When pH data were not available, the median pH value for the ecoregion, a pH value from a comparable waterbody, or a pH value from a local study in the same waterbody was used as a comparable surrogate. 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 CWA 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. 15 of 52 samples (total) exceed the criteria for COLD, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. However, as pH data were not available, and the median pH value for the ecoregion, a pH value from a comparable waterbody, or a pH value from a local study in the same waterbody was used as a comparable surrogate, section 3.11 will be used as the basis for listing. 4. Pursuant to section 3.11 of the Listing Policy, inclusion of pH data (median pH value for the ecoregion, a pH value from a comparable waterbody, or a pH value from a local study in the same waterbody) in the equation indicates that standards are not met.

Regional Board Decision 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.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 153974, Aluminum	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

314455

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: 15 of 52 samples exceeded the water quality threshold for Aluminum.

Data Reference:

WQX data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters shall not contain chemical constituents in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Evaluation Guideline:

The aluminum criterion for the protection of aquatic life, is pH, total hardness, and dissolved organic carbon (DOC) dependent. When total hardness or DOC data were not available, default values based on the level III ecoregions developed by U.S EPA were substituted (EPA, 2018). When pH data were not available, the median pH value for the ecoregion, a pH value from a comparable waterbody, or a pH value from a local study in the same waterbody was used as a comparable surrogate.

Guideline Reference:

Final Aquatic Life Ambient Water Quality Criteria for Aluminum. EPA-822-R-18-001. Washington, D.C.: Office of Water, USEPA.

Spatial Representation:

The samples were collected at 1 monitoring site: CALWR_WQX-KG000000 (North Bay Aqueduct at Barker Slough Pumping Plant).

Temporal Representation:

The samples were collected between the dates of 2011-04-20 and 2015-10-20

Environmental Conditions:

QAPP Information:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 153974, Aluminum	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

314454

Pollutant:

Aluminum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed STORET data for Barker Slough (Solano County, in Delta Waterways, northwestern portion) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Aluminum.

Data Reference:

WQX data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Waters shall not contain chemical constituents in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Final Aquatic Life Ambient Water Quality Criteria for Aluminum. EPA-822-R-18-001. Washington, D.C.: Office of Water, USEPA.

Spatial Representation:

The samples were collected at 1 monitoring site: CALWR_WQX-KG000000 (North Bay Aqueduct at Barker Slough Pumping Plant).

Temporal Representation:

The samples were collected between the dates of 2011-03-16 and 2014-12-16

Environmental Conditions:

QAPP Information:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	152078	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

Pollutant:	1,2-Dibromo-3-chloropropane (DBCP)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This waterbody was remapped and split at the Delta Boundary during 2024 cycle. Decisions were reassessed based on the new spatial representation. Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 152078, 1,2-Dibromo-3-chloropropane (DBCP)	Region 5
Barker Slough (in Delta Waterways, northwestern portion)

LOE ID:

309046

Pollutant:

1,2-Dibromo-3-chloropropane (DBCP)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

A total of 77 samples were analyzed. The sample results were all below the reporting limit and could not be used in the assessment because they do not meet the Quantification of Chemical Concentrations requirements in section 6.1.5.5 of the Listing Policy. "When the sample value is less than the quantitation limit and the quantitation limit is greater than the water quality standard, objective, criterion, or evaluation guideline, the result shall not be used in the analysis."

Data Reference:

Data for Metals, Nutrients, Inorganics, Organics, and Pesticides in Regions 2,5 and 6, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for 1, 2-Dibromo-3-Chloropropane(DBCP) incorporated by reference in the Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins is 0.20 ug/L (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River Basins. 4th ed

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Barker Slough (Solano County, in Delta Waterways, northwestern portion) was collected at 1 monitoring site [ North Bay Aqueduct at Barker Slough Pumping Plant]

Temporal Representation:

Data was collected over the time period 1/21/2004 10:12:00 AM-6/16/2010 11:25:00 AM.

Environmental Conditions:

Staff is not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

The Quality Assurance Project Plan from Bryte Chemical Laboratory was followed.

QAPP Information Reference(s):