Draft California 2026 Integrated Report (303(d) List/305(b) Report)

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332022

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The minimum dissolved oxygen concentration for waters designated as SPWN is 7.0 mg/L. (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin Basin)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2017-03-21 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332021

Pollutant:

Oxygen, Dissolved

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The minimum dissolved oxygen concentration for waters designated as COLD is 7.0 mg/L. (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin Basin)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2017-03-21 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330008

Pollutant:

Oxygen, Dissolved

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The minimum dissolved oxygen concentration for waters designated as COLD is 7.0 mg/L. (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin Basin)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

WQX from the NWQMP for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330009

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The minimum dissolved oxygen concentration for waters designated as SPWN is 7.0 mg/L. (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin Basin)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

WQX from the NWQMP for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330035

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The minimum dissolved oxygen concentration for waters designated as SPWN is 7.0 mg/L. (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin Basin)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-CARO-1047 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309672

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 12 samples exceeded the water quality standard for Oxygen, Dissolved.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for dissolved oxygen in this water body is 7 mg/L expressed as a 7 day minimum averaging period.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309671

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Oxygen, Dissolved.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for dissolved oxygen in this water body is 7 mg/L expressed as a 7 day minimum averaging period.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309668

Pollutant:

Oxygen, Dissolved

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:

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for dissolved oxygen in this water body is 7 mg/L expressed as a 7 day minimum averaging period.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309667

Pollutant:

Oxygen, Dissolved

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 SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 10 samples exceeded the water quality standard for Oxygen, Dissolved.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for dissolved oxygen in this water body is 7 mg/L expressed as a 7 day minimum averaging period.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309666

Pollutant:

Oxygen, Dissolved

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for dissolved oxygen in this water body is 7 mg/L expressed as a 7 day minimum averaging period.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

SJCDWQC_QAPP_082508_Rev102010_Amended06162015_withSignatures_NoSOPs_Final.pdf, 2017-1227 QAPP AmdmtAprvlNewAnalytes.pdf, 2018-0423 SJD QAPPaprvl.pdf, ESJ_Delta_QAPP_Amend_Approval.pdf, FieldQC_QAPP_Amend_030218.pdf, ILRP_SJC_QAPP_Amendt_SedLabChangeWsigs.pdf, SJCDWQC_QAPP_Amendment_Sampling SOP.pdf, SJD QAPP AmdmtFildQualContrSamplReqmntSigned.pdf

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309390

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Aquatic Life Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Twenty-one samples were taken from the Mokelumne River between 2004 and 2006. Five of the twenty-one samples fell below the Water Quality Objective for minimum dissolved oxygen content in surface water.

Data Reference:

Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program

Monitoring and Reporting Program, Order Nos. R5-2003-0826, R5-2005-0833, and R5-2008-0005 for Coalition Groups Under Resolution No. R5-2003-0105, Conditional Waiver of Waste Discharge Requirements for Discharges From Irrigated Lands Within the Central Valley Region

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the Sacramento/San Joaquin River Basin Plan the (COLD) Cold Freshwater Habitat criterion is a Minimum Dissolved Oxygen content of 7mg/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:

Samples were collected from the Mokelumne River at Bruella Road and at the Fish Hatchery.

Temporal Representation:

Samples were collected between August 2004 and September 2006. Samples were collected at bi-monthly and monthly intervals.

Environmental Conditions:

QAPP Information:

Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160548, Oxygen, Dissolved	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309665

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for dissolved oxygen in this water body is 7 mg/L expressed as a 7 day minimum averaging period.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152235	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Chlorpyrifos
Final Listing Decision:	Delist from 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (being addressed by USEPA approved TMDL)(2020)
Revision Status	Revised
Reason for Delisting:	Applicable WQS attained; reason for recovery unspecified
TMDL Name:	Delta Diazinon and Chlorpyrifos Project
TMDL Project Code:	185
Date TMDL Approved by USEPA:	10/10/2007
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Zero of the 87 samples exceeded the evaluation guideline for aquatic life. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from 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. The Delta Diazinon and Chlorpyrifos Project was approved by USEPA on 10/10/2007. 4. Zero of the 87 samples exceeded the evaluation guideline for aquatic life and this does not exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 5. Pursuant to section 4.11 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 be removed from the section 303(d) list because applicable water quality standards for the pollutant 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 152235, Chlorpyrifos	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309453

Pollutant:

Chlorpyrifos

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (4 day average)(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 (with minor corrections to significant figures as described in Beaulaurier et al., 2005).

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

Prepared by Michael L. Johnson LLC for the Irrigated Lands Program. 2010. Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0) ., Prepared by Michael L. Johnson LLC for the Irrigated Lands Program. 2015. Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0) ., Michael L. Johnson LLC. 2015. Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition .

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152235, Chlorpyrifos	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309444

Pollutant:

Chlorpyrifos

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:

Data Reference:

Water Quality Assessment Data for the 2018 solicitation cycle submitted through CEDEN for San Joaquin County Delta Water Quality Coalition

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:

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:

The samples were collected at 1 monitoring site(s) (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2015-09-15

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for San Joaquin County Delta Water Quality Coalition

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

Line of Evidence (LOE) for Decision ID 152235, Chlorpyrifos	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309381

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Seventeen water samples were collected from Mokelumne River from August 2004 through September 2006, representing fifteen calculated 4-day average chlorpyrifos concentrations and five 1-hour average chlorpyrifos concentrations. Zero of the fifteen available calculated 4-day average chlorpyrifos concentrations exceeded the 4-day average chlorpyrifos criterion of 0.015 ug/L. Zero of the fifteen available 1-hour average chlorpyrifos concentrations exceeded the 1-hour average chlorpyrifos criterion of 0.025 ug/L. Two samples had concentrations less than quantitation limit (0.0254 ug/L), which is greater than the chlorpyrifos water quality criteria concentrations. Therefore, in accordance with Section 6.1.5.5 of the Listing Policy, the results for these samples were not used in this analysis.

Data Reference:

Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program

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. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.

Objective/Criterion Reference:

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

Objective/Criterion Reference:

Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game

Evaluation Guideline:

California Department of Fish and Game Hazard Assessment Chlorpyrifos Criteria: 0.015 ug/L as a 4-day average chlorpyrifos concentration, and 0.025 ug/L as a 1-hour average chlorpyrifos concentration, not to be exceeded more that once every three years.

Guideline Reference:

Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game

Spatial Representation:

Samples were collected from the Mokelumne River at Bruella Road and at the Fish Hatchery.

Temporal Representation:

Samples were collected monthly between August 2004 and September 2006.

Environmental Conditions:

QAPP Information:

Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152235, Chlorpyrifos	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309399

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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. (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin River Basin)

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:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	160545	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Copper
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2024)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	LOEs for this waterbody-pollutant combination from previous cycles were reassessed according to a new assessment method. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Six lines of evidence are available in the administrative record to assess pollutant. This listing is based on data prior to 2006. Zero out of twenty-three samples exceed the criteria for aquatic life. Zero out of seven samples exceed the objective for MUN. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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 out of twenty-three samples exceed the criteria for aquatic life. This listing is based on data prior to 2006, and does not support a weight of evidence to delist based upon the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 160545, Copper	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309355

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Evaluation Guideline:

Unspecified

Guideline Reference:

San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160545, Copper	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309366

Pollutant:

Copper

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:

Zero of the 16 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for Copper.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Toxics Rule 4-day average criteria for dissolved Copper.

Objective/Criterion Reference:

Water Quality Standards 2000. Establishment of numeric criteria for priority toxic pollutants for the State of California: Rules and regulations. Federal Register Vol. 65, No. 97. Washington, D.C.: Environmental Protection Agency

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at Mokelumne River at New Hope Road. Samples were collected at Mokelumne River at Van Assen Co. Park.

Temporal Representation:

The samples were collected from Nov 28 2000 to Nov 19 2002

Environmental Conditions:

QAPP Information:

Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160545, Copper	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331046

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary Maximum Contaminant Level for copper incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 1.0 mg/L assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-05-21 and 2020-05-20

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160545, Copper	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331059

Pollutant:

Copper

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved copper criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is hardness dependent. The criterion when calculated using a default hardness of 100 mg/L is 9 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-02-05 and 2020-05-20

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160545, Copper	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

345856

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2010-06-08 and 2010-06-08

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 160545, Copper	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346317

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2011-12-13 and 2016-08-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	160553	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Toxicity
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2024)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
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 removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Seven lines of evidence are available in the administrative record to assess pollutant. Eighteen of the 82 water samples, reported as total fraction or as fraction not reported, exceed the objective for the aquatic life beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. Eighteen of the 82 water samples, reported as total fraction or as fraction not reported, exceed the objective for the aquatic life beneficial use. This exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 160553, Toxicity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309375

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Zero of the 3 samples tested with Hyalella azteca were toxic.

Data Reference:

Monitoring Data from the Surface Water Ambient Monitoring Program (SWAMP), San Joaquin River Basin - 2007 Data Review

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. This objective applies regardless of whether the toxicity is caused by a single substance or the interactive effect of multiple substances. (CVRWQCB, 2007)

Objective/Criterion Reference:

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:

Statistically significant difference from control using a t-test with 10-day Hyalella azteca sediment toxicity tests.

Guideline Reference:

Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates, Second Edition. U.S. Environmental Protection Agency Office of Research and Development, Duluth, MI , U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-600/R-99/064

Spatial Representation:

Samples were collected from two locations: Mokelumne River at New Hope Road and Mokelumne River at Van Assen Co. Park.

Temporal Representation:

Samples were collected from May 2002 to April 2003.

Environmental Conditions:

QAPP Information:

Data quality: Good. Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 160553, Toxicity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309372

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

None of the 3 samples tested with Ceriodaphnia dubia were toxic and violated the narrative toxicity objective.

Data Reference:

Monitoring Data from the Surface Water Ambient Monitoring Program (SWAMP), San Joaquin River Basin - 2007 Data Review

SWAMP Data:

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:

Statistically significant difference from control using a Fisher Exact analysis with 4-day acute-style toxicity tests.

Guideline Reference:

Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. U.S. Environmental Protection Agency Office of Water, Washington, DC EPA-821-R-02-012

Spatial Representation:

Samples were collected from two locations: Mokelumne River at New Hope road and Mokelumne River at Van Assen Co. Park.

Temporal Representation:

The samples were collected from October 2001 to December 2004.

Environmental Conditions:

QAPP Information:

Data quality: Excellent. Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 160553, Toxicity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309391

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Fifty-one samples were collected to evaluate water toxicity. Fourteen of the samples exhibited significant toxicity. The toxicity tests included survival of Ceriodaphnia dubia, total cell count of Selenastrum capricornutum and survival of Pimephales promelas. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location with the same lab sample id (if provided).

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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. Region 5 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:

Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. For SWAMP data exceedances are counted with the significant effect code SL. SL is defined as the result being significant compared to the negative control based on a statistical test, less than stated the alpha level, AND less than the evaluation threshold. This data set reports a simple pass/fail (Yes/No) code to report toxicity that is equivalent to the SWAMP SL code.

Guideline Reference:

Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. Fourth Edition. Office of Water, U.S. Environmental Protection Agency. Washington, D.C. EPA-821-R-02-013

Spatial Representation:

The samples were collected at Mokelumne River at Bruella Rd and Mokelumne River at Fish Hatchery.

Temporal Representation:

The samples were collected from August 2004 to August 2010.

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160553, Toxicity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309392

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Nine samples were collected to evaluate sediment toxicity. None of the samples exhibited significant toxicity. The toxicity tests included survival of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location with the same lab sample id (if provided).

Data Reference:

Data for Various Pollutants in Sacramento Valley Water Quality Coalition, 2005-2009.

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:

Toxicity is defined as a statistically significant effect in the sample exposure compared to the control using EPA-recommended hypothesis testing. For SWAMP data exceedances are counted using the significant effect code: S equals significant, SG equals significantly greater and SL equals significantly lower. If a sample has any one of these codes, it will be considered an exceedance.

Guideline Reference:

Spatial Representation:

The samples were collected at Mokelumne River at Bruella Rd.

Temporal Representation:

The samples were collected from September 2004 and to August 2008.

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition.

QAPP Information Reference(s):

Quality Assurance Project Plan for Sacramento Valley Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 160553, Toxicity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

347502

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

4 of the 25 samples collected by San Joaquin County Delta Water Quality Coalition for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day and the same location. The following organisms and parameters were utilized for the toxicity tests: Selenastrum capricornutum for Total Cell Count, Hyalella azteca for Survival. The following tests exhibited toxicity: Selenastrum capricornutum for Total Cell Count on 2019-05-21, Selenastrum capricornutum for Total Cell Count on 2020-01-22, Selenastrum capricornutum for Total Cell Count on 2020-07-22, Hyalella azteca for Survival on 2021-06-08.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Evaluation Guideline:

The sample is toxic when the response of the organisms exposed to the sample is significantly different (worse) than the response of the organisms exposed to the laboratory control based on statistical hypothesis testing. An exceedance is counted when the significant effect code is "Significant; Less Similarity," which means that the sample result is significantly different than the control result, and the percent effect is greater than the evaluation threshold. The default evaluation threshold is 20% unless otherwise stated.

Guideline Reference:

Spatial Representation:

The samples were collected at monitoring site: 531XMRABR ( Mokelumne River @ Bruella Rd ).

Temporal Representation:

The samples were collected between the dates of 2018-11-13 and 2021-09-14.

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160553, Toxicity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

347494

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

0 of the 4 samples collected by San Joaquin County Delta Water Quality Coalition for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) exhibited toxicity. A sample may have multiple toxicity test results, but will only be counted once. A sample is defined as being collected on the same day and the same location. The following organisms and parameters were utilized for the toxicity tests: Hyalella azteca for Survival.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at monitoring site: 531XMRABR ( Mokelumne River @ Bruella Rd ).

Temporal Representation:

The samples were collected between the dates of 2019-03-19 and 2020-09-16.

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160553, Toxicity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309377

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Zero of the 3 samples tested with Pimephales promelas were toxic and violated the narrative toxicity objective.

Data Reference:

Monitoring Data from the Surface Water Ambient Monitoring Program (SWAMP), San Joaquin River Basin - 2007 Data Review

SWAMP Data:

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:

Statistically significant difference from control using a Fisher Exact analysis with 4-day acute-style toxicity tests.

Guideline Reference:

Spatial Representation:

Samples were collected from two locations: Mokelumne River at New Hope Road and Mokelumne River at Van Assen Co. Park.

Temporal Representation:

Samples were collected from October 2001 to December 2004.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)


DECISION ID	166839	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Zinc
Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2024)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
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 removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Five lines of evidence are available in the administrative record to assess pollutant. 303(d) listing decisions made prior to 2006 were not held in an assessment database. Available data shows that zero of 16 water samples, reported as a dissolved fraction, exceed the guideline for aquatic life and one of four samples, reported in the dissolved fraction, 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 removing this water segment-pollutant combination from 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. Available data shows that zero of 16 water samples, reported as a dissolved fraction, exceed the guideline for aquatic life and one of four samples, reported in the dissolved fraction, exceed the water quality objective for MUN and this is insufficient to delist this water body according to Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be removed from the section 303(d) list because applicable water quality standards for the pollutant are being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 166839, Zinc	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346800

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary Maximum Contaminant Level for zinc incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 5.0 mg/L assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2011-11-15 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 166839, Zinc	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309356

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Evaluation Guideline:

Unspecified

Guideline Reference:

SWAMP data entered by SWRCB into BDAT database

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 166839, Zinc	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346136

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP BDAT data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for Zinc.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531SJC512 (Mokelumne River @ Van Assen Co. Park).

Temporal Representation:

The samples were collected between the dates of 2002-06-24 and 2002-06-24

Environmental Conditions:

QAPP Information:

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 166839, Zinc	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346140

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Various Pollutants in Visalia, 2005-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531SJC512 (Mokelumne River @ Van Assen Co. Park).

Temporal Representation:

The samples were collected between the dates of 2002-06-24 and 2002-06-24

Environmental Conditions:

QAPP Information:

Placeholder reference for data that does not have a QAPP but was collected prior to the QAPP requirements.

QAPP Information Reference(s):

This is a placeholder for previously assessed data that does not have quality assurance information but would require it under newly developed policies. These LOEs were previously assessed and approved at the Regional, State and Federal level in past cycles. The LOEs needed to be moved and/or reassessed but required this reference code for movement within the decision making database.

Line of Evidence (LOE) for Decision ID 166839, Zinc	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309368

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Zero of the 16 samples collected by the Surface Water Ambient Monitoring Program exceeded the calculated CTR CMC for dissolved zinc

Data Reference:

San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Dissolved zinc levels should not exceed the calculated CTR limit based on the formula: Criteria Maximum Concentration=EXP((0.8473*LN(hardness))+0.884)*(0.978)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the Mokelumne River at New Hope Road and at Van Assen Co. Park.

Temporal Representation:

The samples were collected between November 28, 2000 and November 19, 2002

Environmental Conditions:

QAPP Information:

Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):


DECISION ID	169312	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Mercury
Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2024)
Revision Status	Revised
Sources:	Agricultural Return Flows \| Atmospheric Deposition \| Highway/Road/Bridge Runoff \| Industrial Point Sources \| Municipal Point Sources \| Natural Sources \| Resource Extraction \| See TMDL documentation \| Urban Runoff/Storm Sewers
TMDL Name:	Delta Methylmercury TMDL Project
TMDL Project Code:	128
Date TMDL Approved by USEPA:	10/20/2011
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. In the 2022 Cycle mercury LOEs were updated to reflect the statewide mercury objectives. This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1, 4.4, 4.5, and 4.11 of the Listing Policy. Under section 4.1, 4.4, and 4.5 a single line of evidence is necessary to assess listing status. Under section 4.11 when all other listing factors do not result in the listing of a water segment, but information indicates non-attainment of standards, a water segment shall be evaluated to determine whether the weight of evidence demonstrates that water quality standard is not attained. If the weight of evidence indicates non-attainment, the water segment shall be placed on the CWA section 303(d) List. The COMM beneficial use has not been designated to this waterbody. While there is not a specific health advisory for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways), in 2022 OEHHA released Statewide Health Advisory and Guidelines for Eating Fish from California’s Rivers, Streams, and Creeks without Site-Specific Advice for mercury. Fishing occurs in Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) and the fish species largemouth bass, rainbow trout, and Sacramento sucker used for the assessments are part of 2022 Advisory. Additionally, data were collected in this waterbody by the Surface Water Ambient Monitoring Program to monitor pollutants in fish tissue for the purpose of evaluating risks to human health from consumption. The weight of evidence of the data and information indicate water quality standards are not attained. One line of evidence are available in the administrative record to assess the pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the 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. 14 of 30 samples exceed the site specific objective for tissue in trophic level 3 and 4 fish. These samples exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

Regional Board Decision Recommendation:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 169312, Mercury	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309442

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Total

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:

Fish were sampled for tissue analysis at one location from this reach. A total of 14 out of 30 samples exceeded the Water Quality Control Plan fish tissue criterion for human health for trophic level 3 and 4 fish. The average wet weight mercury concentration in fish tissue was 0.20 ppm for all 30 samples collected. The number of fish collected per sample, the measured mercury concentrations in fish tissue, and the number of exceedances are, by species:

Largemouth Bass- 12 samples, 0.09-0.43 ppm (average 0.24 ppm), 6 exceedances;
Rainbow Trout- 9 samples, 0.03-0.05 ppm (average 0.04 ppm), no exceedances;
Sacramento Sucker- 9 samples, 0.1-0.41 ppm (average 0.3 ppm), 8 exceedances.

All 30 samples were collected from fish with total lengths greater than 150 mm, which represent fish most commonly caught and consumed by sport fishers and their families.

Data Reference:

Fish Mercury Project, Year 1 Annual Report, Sport Fish Sampling and Analysis. Collaborating parties: San Francisco Estuary Institute, California Department of Fish and Game, Moss Landing Marine Laboratories, California Office of Environmental Health Hazard Assessment. Final Technical Report. CBDA Project # ERP 02D-P6729. May 2007

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

For the Sacramento-San Joaquin Delta and Yolo Bypass waterways listed in Appendix 43, the average methylmercury concentrations shall not exceed 0.08 and 0.24 mg methylmercury/kg, wet weight, in muscle tissue of trophic level 3 and 4 fish. Respectively (150-500 mm total length). The average methylmercury concentrations shall not exceed 0.03 mg methylmercury/kg, wet weight, in whole fish less than 50 mm in length. (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin River Basin)

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 at one location from the Mokelumne River near Lodi Lake, upstream of Woodbridge Dam.

Temporal Representation:

Fish samples were collected during one sampling event from 9/12/2005 to 9/13/2005.

Environmental Conditions:

QAPP Information:

Data quality: Excellent.. Quality Control for all of the elements described in section 6.1.4 of the Policy was conducted in accordance with the Laboratory QAPP developed by Moss Landing Marine Laboratories (MLML, 2005). This data was also collected and analyzed in accordance with the CALFED Mercury Project QAPP (Puckett and van Buuren, 2000).

QAPP Information Reference(s):

Quality Assurance Project Plan Screening Study of Bioaccumulation in California Lakes and Reservoirs. Moss Landing Marine Labs. Prepared for SWAMP BOG, 49 pages plus appendices and attachments


DECISION ID	152272	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 152272, Aldicarb	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309446

Pollutant:

Aldicarb

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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. (Water Quality Control Plan for the Sacramento and San Joaquin River Basins).

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Aldicarb is the USEPA Aquatic Life Benchmark of 0.46 ug/L for a fish (chronic).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152272, Aldicarb	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309620

Pollutant:

Aldicarb

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 ILRP_SJCDWQC data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 15 samples exceeded the water quality threshold for Aldicarb.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Aldicarb is the USEPA Aquatic Life Benchmark of 0.46 ug/L for a fish (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	165289	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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 165289, Aldrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309505

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Aldrin. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Discharges shall not result in pesticide concentrations in bottom sediments or aquaticlife that adversely affect beneficial uses. (Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River 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:

National Academy of Science guidelines (NAS 1972) establish a maximum Aldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Data for this line of evidence were collected between 2012-01-05 and 2012-01-05. When composited fish were collected over multiple days, the first day of fish collection was used as the sample date in the LOE, both for LOE writing, and for averaging period purposes.

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165289, Aldrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309415

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:

Water Board staff assessed Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 15 samples exceed the criterion for Aldrin.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 10/14/2008-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	167742	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 167742, Ammonia	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329678

Pollutant:

Nitrogen, ammonia (Total Ammonia)

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia Freshwater 2013 document.

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 167742, Ammonia	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330756

Pollutant:

Nitrogen, ammonia (Total Ammonia)

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:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-11-13 and 2020-09-16

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	152257	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Arsenic
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 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 152257, Arsenic	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309419

Pollutant:

Arsenic

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 Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 8 samples exceed the criterion for Arsenic.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater for dissolved arsenic is 0.150 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	152273	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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). 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 152273, Atrazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309621

Pollutant:

Atrazine

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

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

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152273, Atrazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309447

Pollutant:

Atrazine

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

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

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152258	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 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 152258, Azinphos-methyl (Guthion)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309420

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 criterion 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 Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 152258, Azinphos-methyl (Guthion)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309448

Pollutant:

Azinphos-methyl (Guthion)

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Azinphos Methyl. Although a total of 42 samples were collected, 42 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 USEPA National Recommended Water Quality Criteria for azinphos methyl for freshwater aquatic life protection is 0.01 ug/l (instantaneous maximum)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	170889	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

Regional Board Conclusion:	Benthic Community Effects are being considered for placement on the CWA section 303(d) List under sections 3.9 of the Listing Policy. Under section 3.9, additional lines of evidence (LOEs) associating the Benthic Community Effects decision with a water or sediment concentration of pollutants other than benthic-macroinvertebrate bioassessment or habitat assessment LOEs are necessary to place a water body on the 303(d) List for Benthic Community Effects. One line of evidence evaluating benthic-macroinvertebrate bioassessment data is available in the administrative record to assess this indicator. One of one benthic-macroinvertebrate samples exceed the California Stream Condition Index (CSCI) impairment threshold. However, a minimum of two benthic-macroinvertebrate samples are needed to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing Benthic Community Effects in this waterbody segment 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 does not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. One of one benthic-macroinvertebrate bioassessment samples had CSCI scores below 0.79. The available information is insufficient to determine whether the waterbody/pollutant combination should be placed on the 303(d) List of impaired waters at this time. 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:

Line of Evidence (LOE) for Decision ID 170889, Benthic Community Effects	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

352627

Pollutant:

Benthic-Macroinvertebrate Bioassessments

LOE Subgroup:

Population/Community Degradation

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Benthic macroinvertebrate surveys

Data Used to Assess Water Quality:

Water Board staff assessed data for 531CR0032 to determine beneficial use support and the results are as follows: 1 of 1 samples exceeded the water quality standard. CSCI scores were from 0.441402487 to 0.441402487 .

Data Reference:

Benthic, Habitat from the EPA National Rivers and Streams Assessment for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.

Objective/Criterion Reference:

Evaluation Guideline:

The California Stream Condition Index (CSCI) is a biological scoring tool that helps aquatic resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score is calculated by comparing the expected condition with actual (observed) results (Rhen, A.C. et al., 2015). CSCI scores range from 0 (highly degraded) to greater than 1 (equivalent to reference). CSCI scoring of biological condition are as follows (per the scientific paper supporting the development of the CSCI scoring tool): greater than or equal to 0.92 = likely intact condition, 0.91 to 0.80 = possibly altered condition, 0.79 to 0.63 = likely altered condition, less than or equal to 0.62 = very likely altered condition. Sites with scores below 0.79 are considered to have exceeded the water quality objective for the aquatic life beneficial use.)

Guideline Reference:

Bioassessment in complex environments: designing an index for consistent meaning in different settings

Spatial Representation:

The samples were collected at 1 monitoring site: 531CR0032 (Mokelumne River ~2mi below Hwy 99).

Temporal Representation:

Samples were collected from 2018-06-12 to 2018-06-12.

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program


DECISION ID	160556	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Bifenthrin
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:	Previously considered water quality data was reevaluated according to new guidelines as part of this assessment. Lines of evidence have been retired and/or replaced to reflect this change. 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 160556, Bifenthrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309610

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

9 water samples were collected from Mokelumne River from September 2005 through September 2006 representing 9 concentrations.Water Board staff assessed data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the water quality threshold for Bifenthrin.

Data Reference:

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 Bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Bifenthrin 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.

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

Guideline Reference:

Spatial Representation:

Mokelumne River at Bruella Road and Fish Hatchery.

Temporal Representation:

Samples were collected at various intervals (monthly) from September 2005 through September 2006.

Environmental Conditions:

QAPP Information:

Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160556, Bifenthrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309612

Pollutant:

Bifenthrin

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:

Eight samples were collected and analyzed for Bifenthrin. The reporting limit is greater than the evaluation guideline value for all 8 samples; therefore, the data could not be evaluated for exceedances. Therefore, 0 samples, 0 exceedances.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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:

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

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/4/2007.

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 160556, Bifenthrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330848

Pollutant:

Bifenthrin

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Bifenthrin. Although a total of 18 samples were collected, 17 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of bifenthrin 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.

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

The samples were collected between the dates of 2019-06-18 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	152274	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Boron
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 3.1 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 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 applicable water quality standards for the pollutant are not exceeded.

Line of Evidence (LOE) for Decision ID 152274, Boron	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309449

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water 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:

Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water, including irrigation of various types of crops and stock watering. At or below the limits presented in the Water Quality Goals tables, agricultural uses of water should not be limited. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. The criteria for boron is 700 ug/L (0.7 mg/L).

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152219	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Cadmium
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 152219, Cadmium	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309450

Pollutant:

Cadmium

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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152219, Cadmium	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309358

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

None of the 9 samples collected by the Surface Water Ambient Monitoring Program exceeded the calculated CTR criterion for dissolved cadmium

Data Reference:

San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Dissolved cadmium levels should not exceed the calculated limit based on the formula: Criteria Maximum Concentration (1-hour Average dissolved)=(EXP(1.128*LN(hardness)-3.6867))*(1.136672-(LN(hardness)*0.041838))

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the Mokelumne River at New Hope Road and at Van Assen County Park

Temporal Representation:

The samples were collected between August 28, 2001 and November 19, 2002

Environmental Conditions:

QAPP Information:

Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):


DECISION ID	152243	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Carbaryl
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 152243, Carbaryl	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309397

Pollutant:

Carbaryl

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 water quality criterion for freshwater aquatic life for carbaryl is 2.1 µg/L.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 152243, Carbaryl	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309452

Pollutant:

Carbaryl

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 USEPA recommended water quality criteria for freshwater aquatic life for carbaryl is 2.1 µg/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152244	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 152244, Carbofuran	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309398

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 92-3, 1992).

Guideline Reference:

Hazard Assessment of the Insecticide Carbofuran to Aquatic Organisms in the Sacramento River System

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 152244, Carbofuran	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309451

Pollutant:

Carbofuran

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 interim water quality criterion for the protection of sensitive aquatic organisms from Carbofuran is 0.5 ug/l (DFG 92-3, 1992).

Guideline Reference:

Hazard Assessment of the Insecticide Carbofuran to Aquatic Organisms in the Sacramento River System

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	165273	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Chlordane
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. 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 165273, Chlordane	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309530

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Total Chlordanes. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum total Chlordane concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165273, Chlordane	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309533

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Total Chlordanes. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for total chlordane in fish tissue is 3.9 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	160544	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160544, Chloride	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346242

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed DFW_ABL_Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the upper limit of the range for Chloride. Additionally, 0 of the 1 samples fall within the range, and 1 of 1 samples fall below the threshold.

Data Reference:

Habitat, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference into the Water Quality Control Plan for the Sacramento and San Joaquin River Basins specifies a range for chloride of 250-500 mg/L assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531CR1047 (Mokelumne River -1047).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160544, Chloride	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329799

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

WQX from the NWQMP for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 160544, Chloride	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329730

Pollutant:

Chloride

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-CARO-1047 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5


DECISION ID	160566	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160566, Clothianidin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331030

Pollutant:

Clothianidin

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:

Data Reference:

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 evaluation guideline for clothianidin is the USEPA Aquatic Life Benchmark of 0.05 ug/L for an invertebrate (chronic).

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-05-21 and 2020-05-20

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):


DECISION ID	152245	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. 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 for Cold Freshwater Habitat. Zero of the 57 samples, reported as a total concentration or with the fraction not reported, exceed the guideline for the Cold Freshwater Habitat use. 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 57 samples, reported as a total concentration or with the fraction not reported, exceed the guideline for the Cold Freshwater Habitat use 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 152245, Cyanazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309400

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 Navicula pelliculosa (freshwater diatom) for cyanazine is 4.8 ug/L (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152245, Cyanazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309454

Pollutant:

Cyanazine

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for cyanazine is the EC50 of 4.8 ug/L for Navicula pelliculosa (freshwater diatom) (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	160560	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Cyfluthrin
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:	Previously considered water quality data was reevaluated according to new guidelines as part of this assessment. Lines of evidence have been retired and/or replaced to reflect this change. 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 160560, Cyfluthrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331153

Pollutant:

Cyfluthrin

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cyfluthrin. Although a total of 19 samples were collected, 19 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cyfluthrin 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.

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-05-21 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160560, Cyfluthrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309614

Pollutant:

Cyfluthrin

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 Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Cyfluthrin, total. Eight samples were not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 Cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Cyfluthrin 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.

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

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/4/2007.

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	160561	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Cyhalothrin, Lambda
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:	Previously considered water quality data was reevaluated according to new guidelines as part of this assessment. Lines of evidence have been retired and/or replaced to reflect this change. 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 160561, Cyhalothrin, Lambda	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331683

Pollutant:

Cyhalothrin, Lambda

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Lambda-cyhalothrin. Although a total of 20 samples were collected, 20 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 lambda-cyhalothrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Lambda-cyhalothrin 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.

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-04-09 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160561, Cyhalothrin, Lambda	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309615

Pollutant:

Cyhalothrin, Lambda

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 Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Cyhalothrin, lambda. Eight samples were not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 Lambda-cyhalothrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Lambda-cyhalothrin 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.

Guideline Reference:

Water Quality Criteria Report for Lambda-cyhalothrin

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 Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/4/2007.

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	160557	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Cypermethrin
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:	Previously considered water quality data was reevaluated according to new guidelines as part of this assessment. Lines of evidence have been retired and/or replaced to reflect this change. 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 160557, Cypermethrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331182

Pollutant:

Cypermethrin

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 18 samples were collected, 18 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Cypermethrin 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.

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-06-18 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160557, Cypermethrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309616

Pollutant:

Cypermethrin

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 Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Cypermethrin, total. Eight samples were not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 Cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Cypermethrin 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.

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

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 Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/4/2007.

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	169227	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
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:	LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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 169227, DDT (Dichlorodiphenyltrichloroethane)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309455

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDT(p,p'). Although a total of 21 samples were collected, 21 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.005 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Line of Evidence (LOE) for Decision ID 169227, DDT (Dichlorodiphenyltrichloroethane)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309528

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD). Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for total DDT in fish tissue is 15 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 169227, DDT (Dichlorodiphenyltrichloroethane)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309534

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD). Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum total DDT concentration of 1000 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	152278	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(2020)
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. 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 152278, Demeton	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309459

Pollutant:

Demeton

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 USEPA National Recommended Water Quality Criteria toxicity threshold for demeton for freshwater aquatic life protection is 0.1 ug/l (4 day average)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152249	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 152249, Diazinon	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309460

Pollutant:

Diazinon

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 freshwater chronic value for diazinon is 0.1 ug/L (4 day average)(Finlayson, 2004).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152249, Diazinon	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309404

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 criterion 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 Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	152280	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Dichlorvos
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 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 152280, Dichlorvos	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309462

Pollutant:

Dichlorvos

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 42 samples were collected, 42 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152279	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 152279, Dicofol	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309461

Pollutant:

Dicofol

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Dicofol is the USEPA Aquatic Life Benchmark of 4.4 ug/L for a fish (chronic).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152279, Dicofol	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309619

Pollutant:

Dicofol

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 ILRP_SJCDWQC data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 30 samples exceeded the water quality threshold for Dicofol.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Dicofol is the USEPA Aquatic Life Benchmark of 4.4 ug/L for a fish (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2009-12-08

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	165275	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165275, Dieldrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309506

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Dieldrin. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum Dieldrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165275, Dieldrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309406

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:

Water Board staff assessed Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 30 samples exceed the criterion for Dieldrin.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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).

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165275, Dieldrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309463

Pollutant:

Dieldrin

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 165275, Dieldrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309507

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Waterboard staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows: Zero of Zero samples exceeded the water quality threshold for Dieldrin. Although data was collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite), all 1 sample(s) had to be thrown out due to quantitation issues.

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for dieldrin in fish tissue is 0.32 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	152283	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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. 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 152283, Dimethoate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309467

Pollutant:

Dimethoate

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152283, Dimethoate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309618

Pollutant:

Dimethoate

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	152251	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 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 152251, Disulfoton	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309407

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 for disulfoton in freshwater (0.05 ug/L) is an aquatic life maximum (instantaneous) level.

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 152251, Disulfoton	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309468

Pollutant:

Disulfoton

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Disulfoton. Although a total of 42 samples were collected, 42 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 evaluation guideline for disulfoton is the USEPA Aquatic Life Benchmark of 0.01 ug/L for chronic toxicity in invertebrates (7 day average).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152282	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Diuron
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 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 applicable water quality standards for the pollutant are not exceeded.

Line of Evidence (LOE) for Decision ID 152282, Diuron	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309466

Pollutant:

Diuron

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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:

Aquatic life should not be affected unacceptably if the 4-day average concentration of diuron does not exceed 1.3 ug/L (UC Davis Aquatic Life Criteria).

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: III. Diuron. Reviews of Environmental Contamination and Toxicology 216:105-141.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	165276	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Endosulfan
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:	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. 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 165276, Endosulfan	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309510

Pollutant:

Endosulfan

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Endosulfan. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for endosulfan (l and ll) in fish tissue is 13,000 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008; USEPA, 2000)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Guideline Reference:

Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165276, Endosulfan	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309511

Pollutant:

Endosulfan

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Endosulfan. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum Endosulfan, Total concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	165277	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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). There is insufficient information to determine if fishing occurs at this waterbody; therefore, beneficial use support for COMM cannot be determined at this time. If new information is submitted during subsequent cycles, this assessment may be revised. Additional data and information may include information demonstrating that fishing is occurring in this waterbody. 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:

Line of Evidence (LOE) for Decision ID 165277, Endrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309409

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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)

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165277, Endrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309513

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Endrin. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum Endrin concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165277, Endrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309469

Pollutant:

Endrin

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 165277, Endrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309512

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Endrin. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for endrin in fish tissue is 660 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008; USEPA, 2000)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Guideline Reference:

Guidance for Assessing Chemical Contaminant Data for Use In Fish Advisories Volume 1: Fish Sampling and Analysis

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	160563	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160563, Esfenvalerate/Fenvalerate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331529

Pollutant:

Esfenvalerate/Fenvalerate

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Esfenvalerate. Although a total of 18 samples were collected, 18 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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.

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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-06-18 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	160562	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160562, Fenpropathrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331570

Pollutant:

Fenpropathrin

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.0015 ug/L for an invertebrate (chronic).

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-04-09 and 2020-09-16

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):


DECISION ID	160546	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(2024)
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. LOE 67594 has been replaced by LOE 221787 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 because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 160546, Glyphosate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309471

Pollutant:

Glyphosate

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Glyphosate is the USEPA Aquatic Life Benchmark of 11900 ug/L for a vascular plant (acute).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-07-19

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160546, Glyphosate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331583

Pollutant:

Glyphosate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for Glyphosate incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.7 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-11-29 and 2020-07-22

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160546, Glyphosate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331605

Pollutant:

Glyphosate

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 evaluation guideline for glyphosate is the USEPA Aquatic Life Benchmark of 11900 ug/L for a vascular plant (acute).

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-11-29 and 2020-07-22

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160546, Glyphosate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309622

Pollutant:

Glyphosate

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Glyphosate is the USEPA Aquatic Life Benchmark of 11900 ug/L for a vascular plant (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	165278	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165278, Heptachlor	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309413

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 10/14/2008-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165278, Heptachlor	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309525

Pollutant:

Heptachlor

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Heptachlor. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum Heptachlor concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	165279	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165279, Heptachlor epoxide	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309423

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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).

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 10/14/2008-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165279, Heptachlor epoxide	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309518

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Waterboard staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows: Zero of Zero samples exceeded the water quality threshold for Heptachlor Epoxide. Although data was collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite), all 1 sample(s) had to be thrown out due to quantitation issues.

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for heptachlor epoxide in fish tissue is 0.93 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008; OEHHA, 1999)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Guideline Reference:

Public Health Goal for Heptachlor and Heptachlor Epoxide in Drinking Water

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165279, Heptachlor epoxide	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309526

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Heptachlor Epoxide. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum Heptachlor Epoxide concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	165280	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Hexachlorobenzene/ HCB
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:	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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165280, Hexachlorobenzene/ HCB	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309519

Pollutant:

Hexachlorobenzene/ HCB

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Hexachlorobenzene. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for hexachlorobenzene in fish tissue is 2.8 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008; OEHHA, 2005)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Guideline Reference:

Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	160555	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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:

Line of Evidence (LOE) for Decision ID 160555, Imidacloprid	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331649

Pollutant:

Imidacloprid

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Imidacloprid. Although a total of 6 samples were collected, 6 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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.

Objective/Criterion Reference:

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of imidacloprid does not exceed 0.016 ug/L.

Guideline Reference:

Water Quality Criteria Report for Imidacloprid Phase III: Application of the pesticide water quality criteria methodology. Department of Environmental Toxicology. University of California, Davis

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-05-21 and 2020-07-22

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	165308	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Indicator Bacteria
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 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. Eight lines of evidence are available in the administrative record to assess this pollutant. Historical bacteria LOEs (pre-2010 data) have been removed and data has been compared to the newer E. coli bacteria water quality objective. Six of the 118 samples, expressed as a Statistical Threshold Value, exceed the objective for REC-1. 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. Six of the 118 samples, expressed as a Statistical Threshold Value, exceed the objective for REC-1 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:

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309498

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows: 4 of the 71 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective applicable to all waters, except Lake Tahoe, where the salinity is less than 10 parts per thousand (ppth) 95 percent or more of the time is a STATISTICAL THRESHOLD VALUE (STV) of 320 cfu/100 mL not to be exceeded more than 10 percent of the time (calculated monthly).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531XMRABR

Temporal Representation:

The samples were collected between the days of 2010-09-07 and 2016-09-20 .

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309499

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531SJC111

Temporal Representation:

The samples were collected between the days of 2012-06-26 and 2012-06-26 .

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309501

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531SJC110

Temporal Representation:

The samples were collected between the days of 2012-06-26 and 2012-06-26 .

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329490

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and the results are as follows: 0 of the 5 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

Benthic, Field, Habitat, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial use where the salinity is less than 1 parts per thousand 95 percent or more of the time applies a statistical threshold value to E. coli of 320 cfu/100 mL, not to be exceeded by more than 10 percent of samples within a calendar month (ISWEBE 2018).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531SJC512 (Mokelumne River @ Van Assen Co. Park).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2017-10-10 .

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Benthic, Field, Habitat, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329487

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531SJC110 (Mokelumne River at Stillman Maggee Park).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2017-10-10 .

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329439

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

STV

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and the results are as follows: 2 of the 23 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the days of 2018-10-16 and 2020-09-16 .

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329453

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and the results are as follows: 0 of the 5 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

Benthic, Field, Habitat, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The bacteria water quality objective to protect the REC-1 beneficial use for waters where the salinity is equal to or less than 1 part per thousand 95 percent or more of the time applies a rolling six-week geometric mean of E. coli, not to exceed 100 cfu/100 mL (ISWEBE 2018).

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531SJC110 (Mokelumne River at Stillman Maggee Park).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2017-10-10 .

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Benthic, Field, Habitat, Toxicity, WQ from the Surface Water Ambient Monitoring Program for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 165308, Indicator Bacteria	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

329450

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

GeoMean

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and the results are as follows: 0 of the 7 samples exceeded the geomean water quality threshold for E. coli. This is a six week rolling geomean that is calculated weekly.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site(s), station(s): 531SJC512 (Mokelumne River @ Van Assen Co. Park).

Temporal Representation:

The samples were collected between the days of 2017-06-14 and 2017-10-10 .

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows


DECISION ID	152221	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Lead
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 152221, Lead	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309360

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Zero of the 16 samples collected by the Surface Water Ambient Monitoring Program exceeded the calculated CTR CMC for dissolved lead

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Dissolved lead levels should not exceed the calculated CTR value based on the formula: Criteria Maximum Concentration (1-hour Average, dissolved)=(EXP(1.273*LN(hardness)-1.46))*(1.46203-(LN(hardness)*0.145712))

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the Mokelumne River at New Hope Road and at Van Assen County Park

Temporal Representation:

The samples were collected between November 28, 2000 and November 19, 2002

Environmental Conditions:

QAPP Information:

Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 152221, Lead	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309473

Pollutant:

Lead

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows: 0 of the 19 samples exceeded the water quality threshold for Lead. Although a total of 21 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-01-11 to 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	165282	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165282, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309425

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The gamma-HCH (Lindane) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 10/14/2008-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165282, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309516

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for HCH, gamma-. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum Lindane concentration of 100 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165282, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309520

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for HCH, gamma-. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for lindane in fish tissue is 4.6 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008; OEHHA, 2005)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Guideline Reference:

Air Toxics Hotspots Program Risk Assessment Guidelines. Part ll Technical Support Document for Describing Available Cancer Potency Values.

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	152286	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Linuron
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 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 152286, Linuron	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309474

Pollutant:

Linuron

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Linuron. Although a total of 42 samples were collected, 42 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Linuron is the USEPA Aquatic Life Benchmark of 0.09 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152286, Linuron	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309625

Pollutant:

Linuron

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 ILRP_SJCDWQC data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Linuron. Although a total of 15 samples were collected, 15 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Linuron is the USEPA Aquatic Life Benchmark of 0.09 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2007-02-11 to 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	171272	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(2024)
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. Previously considered water quality data was reevaluated according to new guidelines as part of this assessment. Lines of evidence have been replaced.

Regional Board Decision Recommendation:	The sample results were not assessed because they were above the evaluation guideline and, therefore, could not be quantified with the level of certainty required by the Listing Policy.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 171272, Malathion	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

353092

Pollutant:

Malathion

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 ILRP_SJCDWQC data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Malathion. Although a total of 15 samples were collected, 15 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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:

Aquatic life should not be affected unacceptably if the 4-day average concentration of malathion does not exceed 0.028 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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 171272, Malathion	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309475

Pollutant:

Malathion

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Malathion. Although a total of 42 samples were collected, 42 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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:

Aquatic life should not be affected unacceptably if the 4-day average concentration of malathion does not exceed 0.028 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:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152288	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOE 67775 has been replaced by LOE 221989 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 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 152288, Methidathion	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309479

Pollutant:

Methidathion

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152288, Methidathion	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309623

Pollutant:

Methidathion

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	152287	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 152287, Methiocarb	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309477

Pollutant:

Methiocarb

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Methiocarb is the USEPA Aquatic Life Benchmark of 2.75 ug/L for a invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152287, Methiocarb	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309624

Pollutant:

Methiocarb

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Methiocarb is the USEPA Aquatic Life Benchmark of 2.75 ug/L for a invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	152263	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 152263, Methomyl	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309476

Pollutant:

Methomyl

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 Basin Plan states: \Where valid testing has developed 96-hour LC50 values for aquatic organisms..., the Board will consider one tenth of this value for the most sensitive species tested as the upper limit (daily maximum) for the protection of aquatic life... or [O]ther available information on the pesticide...\" The criteria continuous concentration for Methomyl in the San Joaquin River system is 0.5 ug/L (4-day average). "

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152263, Methomyl	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309427

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 Basin Plan states: "Where valid testing has developed 96-hour LC50 values for aquatic organisms..., the Board will consider one tenth of this value for the most sensitive species tested as the upper limit (daily maximum) for the protection of aquatic life... or [O]ther available information on the pesticide..." The criteria continuous concentration for Methomyl in the San Joaquin River system is 0.5 ug/L (4-day average). (CDFG, 1996)

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	152264	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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, RWQCB staff concludes that the listing decision will not change during the current cycle and the specific waterbody will be reassessed in future cycles. Assessments for Delta Subareas will be phased out of the Integrated Report during future cycles and these data will be reevaluated as part of localized assessments where data is more representative of water quality.

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 152264, Methoxychlor	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309478

Pollutant:

Methoxychlor

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 USEPA National Recommended Water Quality Criteria toxicity threshold for methoxychlor for freshwater aquatic life protection is 0.03 ug/l.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152264, Methoxychlor	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309428

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Total identifiable persistent chlorinated hydrocarbon pesticides shall not be present in the water column at concentrations detectable within the accuracy of analytical methods approved by the Environmental Protection Agency or the Executive Officer (Water Quality Control Plan, Central Valley Region, Sacramento River Basin and San Joaquin River Basin)

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 Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	152265	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 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 152265, Methyl Parathion	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309429

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 California Department of Fish and Game instantaneous aquatic life criterion for Methyl Parathion is 0.08 ug/L.

Guideline Reference:

Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System. California Department of Fish and Game. Environmental Services Division. Administrative Report 92-1

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 152265, Methyl Parathion	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309489

Pollutant:

Methyl Parathion

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Parathion, Methyl. Although a total of 42 samples were collected, 42 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 California Department of Fish and Game instantaneous aquatic life criterion for Methyl Parathion is 0.08 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	165283	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Mirex
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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165283, Mirex	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309540

Pollutant:

Mirex

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Waterboard staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows: Zero of Zero samples exceeded the water quality threshold for Mirex. Although data was collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite), all 1 sample(s) had to be thrown out due to quantitation issues.

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 modified OEHHA Fish Contaminant Goal for mirex in fish tissue is 0.28 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008; OEHHA, 1992)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Guideline Reference:

Expedited Cancer Potency Values and Proposed Regulatory Levels for Certain Proposition 65 Carcinogens.

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	152343	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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. 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 152343, Molinate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309629

Pollutant:

Molinate

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	152289	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Molybdenum
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 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 applicable water quality standards for the pollutant are not exceeded.

Line of Evidence (LOE) for Decision ID 152289, Molybdenum	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309481

Pollutant:

Molybdenum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Agricultural Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water 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:

Water Quality for Agriculture, published by the Food and Agriculture Organization of the United Nations in 1985, contains criteria protective of various agricultural uses of water. These criteria were used to translate narrative water quality objectives for chemical constituents that prohibit chemicals in concentrations that would impair agricultural uses of water. A 10 ug/L criteria is the recommended maximum concentration of molybdenum in irrigation water.

Guideline Reference:

Water Quality for Agriculture, Food and Agriculture Organization of the United Nations - Irrigation and Drainage Paper No. 29, Rev 1, Rome (1985)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	165284	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Nickel
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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165284, Nickel	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309362

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Zero of the 16 samples collected by the Surface Water Ambient Monitoring Program exceeded the calculated CTR CMC for dissolved nickel

Data Reference:

San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Dissolved nickel levels should not exceed the calculated CTR limit based on the formula: Criteria Maximum Concentration (1-hour Average, dissolved)=(EXP(0.846*LN(hardness)+2.255))*(0.998)

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the Mokelumne River at New Hope Road and at Van Assen Co. Park

Temporal Representation:

The samples were collected between November 28, 2000, and November 19, 2002

Environmental Conditions:

QAPP Information:

Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 165284, Nickel	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309483

Pollutant:

Nickel

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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	152225	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Nitrate as Nitrate (NO3)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	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 152225, Nitrate as Nitrate (NO3)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309364

Pollutant:

Nitrate as Nitrate (NO3)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

0 of the 16 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation guideline for Nitrate-N.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows

SWAMP Data:

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:

Nitrate-N levels should not to exceed 100 mg/L (USEPA National Ambient Water Quality Objective)

Guideline Reference:

Spatial Representation:

Samples were collected at Mokelumne River at New Hope Road. Samples were collected at Mokelumne River at Van Assen Co. Park.

Temporal Representation:

The samples were collected from Oct 24 2000 to Jun 25 2002

Environmental Conditions:

QAPP Information:

Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):


DECISION ID	160547	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

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:

Line of Evidence (LOE) for Decision ID 160547, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

331927

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Primary California Maximum Contaminant Level for nitrate + nitrite (as N) incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 10 mg/L (California Code of Regulations, Title 22).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-10-16 and 2020-09-16

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	152292	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Oxamyl (Vydate)
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 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 applicable water quality standards for the pollutant are not exceeded.

Line of Evidence (LOE) for Decision ID 152292, Oxamyl (Vydate)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309486

Pollutant:

Oxamyl (Vydate)

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 evaluation guideline for oxamyl is the USEPA Aquatic Life Benchmark of 27 ug/L for chronic toxicity in invertebrates (7 day average).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	160558	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160558, Oxyfluorfen	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332013

Pollutant:

Oxyfluorfen

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of oxyfluorfen does not exceed 0.14 ug/L (Bower, et al. 2017).

Guideline Reference:

Water quality criteria report for Oxyfluorfen. Phase III: application of the pesticide water quality criteria methodology.

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-11-13 and 2020-03-17

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	165286	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	PCBs (Polychlorinated biphenyls)
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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165286, PCBs (Polychlorinated biphenyls)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309543

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for PCBs (Polychlorinated biphenyls). Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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. (Water Quality Control Plan for the California Regional Water Quality Control Board Central Valley Region, Sacramento and San Joaquin River 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:

The modified OEHHA Fish Contaminant Goal for polychlorinated biphenyls in fish tissue is 2.6 ppb. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day for a 30 year exposure over a 70-year lifetime. This constituent is a carcinogen therefore the risk level is set to one in a million. A cooking reduction factor of 1 is applied for skin-off fillets. (Klasing, S., and R. Brodberg, 2008)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165286, PCBs (Polychlorinated biphenyls)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309529

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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 SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for PCBs (Polychlorinated biphenyls). Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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:

National Academy of Science guidelines (NAS 1972) establish a maximum total PCB Arochlor concentration of 500 ug/Kg (wet weight) in tissue samples for protection of aquatic life from bioaccumulation of toxic substances.

Guideline Reference:

National Academy of Sciences. Water Quality Criteria 1972. EPA-R3-73-033. Washington, D.C.: U.S. Environmental Protection Agency

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	160564	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Paraquat
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:	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 160564, Paraquat	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309627

Pollutant:

Paraquat

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 ILRP_SJCDWQC data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Paraquat. Although a total of 15 samples were collected, 14 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Paraquat is the USEPA Aquatic Life Benchmark of 0.396 ug/L for a nonvascular plant (acute) for Paraquat dichloride.

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Data for this waterbody was collected over the date range 2007-02-11 to 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160564, Paraquat	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332271

Pollutant:

Paraquat

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Paraquat. Although a total of 4 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 evaluation guideline for paraquat is the USEPA Aquatic Life Benchmark of 0.396 ug/L for a nonvascular plant (acute) for Paraquat dichloride.

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-11-13 and 2020-07-22

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160564, Paraquat	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309485

Pollutant:

Paraquat

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Paraquat. Although a total of 23 samples were collected, 23 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Paraquat is the USEPA Aquatic Life Benchmark of 0.396 ug/L for a nonvascular plant (acute) for Paraquat dichloride.

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-01-11 to 2016-07-19

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	160559	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160559, Pendimethalin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332306

Pollutant:

Pendimethalin

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 evaluation guideline for pendimethalin is the USEPA Aquatic Life Benchmark of 5.2 ug/L for a nonvascular plant (acute).

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-01-08 and 2020-03-17

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):


DECISION ID	160565	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Permethrin
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:	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 160565, Permethrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332350

Pollutant:

Permethrin

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 18 samples were collected, 18 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Permethrin 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.

Guideline Reference:

Water Quality Criteria Report for Permethrin

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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-06-18 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160565, Permethrin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309617

Pollutant:

Permethrin

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 Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Permethrin, Total. Eight samples were not used in the assessment because the laboratory data reporting limit(s) was above the objective and therefore the results could not be quantified with the level of certainty required by the Listing Policy.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 Permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of Permethrin 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.

Guideline Reference:

Water Quality Criteria Report for Permethrin

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 Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/4/2007.

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	152293	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 152293, Phorate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309490

Pollutant:

Phorate

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 152293, Phorate	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309626

Pollutant:

Phorate

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	171275	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(2024)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Previously considered water quality data was reevaluated according to new guidelines as part of this assessment. Lines of evidence have been replaced. 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:

Line of Evidence (LOE) for Decision ID 171275, Phosmet	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

353180

Pollutant:

Phosmet

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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 evaluation guideline for phosmet is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 171275, Phosmet	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

353221

Pollutant:

Phosmet

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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 evaluation guideline for phosmet is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	160554	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160554, Pyrethroids	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332615

Pollutant:

Pyrethroids

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Pyrethroids. Although a total of 20 samples were collected, 20 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides 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.

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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-04-09 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160554, Pyrethroids	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332618

Pollutant:

Pyrethroids

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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:

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:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2019-06-18 and 2019-06-18

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	165287	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Selenium
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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165287, Selenium	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309370

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Zero of the 6 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for Selenium.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows

SWAMP Data:

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:

Samples were collected at Mokelumne River at New Hope Road. Samples were collected at Mokelumne River at Van Assen Co. Park.

Temporal Representation:

The samples were collected from Oct 22 2002 to Oct 29 2002

Environmental Conditions:

QAPP Information:

Monitoring was conducted in accordance with the State Water Resources Control Board's Quality Assurance Program Plan for the State of California's Surface Water Ambient Monitoring Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 165287, Selenium	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309436

Pollutant:

Selenium

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 Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Selenium.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.005 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-9/16/2008.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165287, Selenium	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309494

Pollutant:

Selenium

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The selenium criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 5 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 165287, Selenium	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309536

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Fish fillet

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:

Water Board staff assessed SWAMP Sportfish Rivers and Streams data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and the results are as follows 0 of the 1 samples exceeded the water quality threshold for Selenium. Data were collected for 1 fish species (1 composite(s) of Steelhead Rainbow Trout each composed of 5 fish per composite).

Data Reference:

Habitat, Tissue data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

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 OEHHA Fish Contaminant Goal for selenium in fish tissue is 7.4 ppm. This screening level assumes an average body weight of 70 kg and a consumption rate of 32 g/day. A background dietary consumption rate of 0.114 mg/day is applied for this micronutrient. (Klasing, S., and R. Brodberg, 2008)

Guideline Reference:

Development of Fish Contaminant Goals and Advisory Tissue Levels for Common Contaminants in California Sport Fish: Chlordane, DDTs, Dieldrin, Methylmercury, PCBs, Selenium, and Toxaphene

Spatial Representation:

Data was collected from 1 station(s) with the station code(s): 531ADVMOK.

Temporal Representation:

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	160550	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(2024)
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:

Line of Evidence (LOE) for Decision ID 160550, Simazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309496

Pollutant:

Simazine

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160550, Simazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309630

Pollutant:

Simazine

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160550, Simazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332676

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for Simazine incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.004 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-11-13 and 2018-11-13

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160550, Simazine	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332668

Pollutant:

Simazine

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 evaluation guideline for simazine is the USEPA Aquatic Life Benchmark of 6 ug/L for a nonvascular plant (acute).

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2018-11-13 and 2018-11-13

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):


DECISION ID	165459	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

Regional Board Conclusion:	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. Twelve lines of evidence are available in the administrative record to assess this pollutant. One of the 29 samples exceed the 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. 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 the 29 samples exceed the objective for MUN 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. 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 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346560

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:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 2 samples fall within the range, and 2 of 2 samples fall below the threshold.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference into the Water Quality Control Plan for the Sacramento and San Joaquin River Basins specifies a range for specific conductance of 900-1600 uS/cm assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531SJC512 (Mokelumne River @ Van Assen Co. Park).

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332767

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:

Water Board staff assessed San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 5 samples fall within the range, and 5 of 5 samples fall below the threshold.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2017-08-22 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330229

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-CARO-1047 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

WQX from the NWQMP for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330274

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:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346361

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:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 1 samples fall within the range, and 1 of 1 samples fall below the threshold.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531SJC111 (Mokelumne River at Mokelumne Beach RV Park).

Temporal Representation:

The samples were collected between the dates of 2012-06-26 and 2012-06-26

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

345866

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:

Water Board staff assessed ILRP_SJCDWQC data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 7 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 7 samples fall within the range, and 7 of 7 samples fall below the threshold.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2004-10-06 and 2010-12-07

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346358

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:

Water Board staff assessed DFW_ABL_Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 1 samples fall within the range, and 1 of 1 samples fall below the threshold.

Data Reference:

Habitat, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531CR1047 (Mokelumne River -1047).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

345960

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:

Water Board staff assessed City of Visalia data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 1 samples fall within the range, and 1 of 1 samples fall below the threshold.

Data Reference:

Data for Various Pollutants in Visalia, 2005-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531SJC512 (Mokelumne River @ Van Assen Co. Park).

Temporal Representation:

The samples were collected between the dates of 2002-12-23 and 2002-12-23

Environmental Conditions:

QAPP Information:

Placeholder reference for data that does not have a QAPP but was collected prior to the QAPP requirements.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346400

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:

Water Board staff assessed San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 7 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 7 samples fall within the range, and 7 of 7 samples fall below the threshold.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2010-12-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

345894

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:

Water Board staff assessed ILRP_SJCDWQC data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 1 samples fall within the range, and 1 of 1 samples fall below the threshold.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRAFH (Mokelumne River @ Fish Hatchery).

Temporal Representation:

The samples were collected between the dates of 2005-09-20 and 2005-09-20

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346005

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:

Water Board staff assessed San Joaquin River SWAMP Monitoring Data - Drainage Basin Inflows data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 1 samples fall within the range, and 0 of 1 samples fall below the threshold.

Data Reference:

Monitoring Data from the Surface Water Ambient Monitoring Program (SWAMP), San Joaquin River Basin - 2007 Data Review

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: SJC512 (SJC512).

Temporal Representation:

The samples were collected between the dates of 2002-12-23 and 2002-12-23

Environmental Conditions:

QAPP Information:

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

QAPP Information Reference(s):

Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)

Line of Evidence (LOE) for Decision ID 165459, Specific Conductivity	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346383

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:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 0 of the 1 samples fall within the range, and 1 of 1 samples fall below the threshold.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531SJC110 (Mokelumne River at Stillman Maggee Park).

Temporal Representation:

The samples were collected between the dates of 2017-10-10 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	160551	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 160551, Sulfates	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346704

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed DFW_ABL_Monitoring data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the upper limit of the range for Sulfate. Additionally, 0 of the 1 samples fall within the range, and 1 of 1 samples fall below the threshold.

Data Reference:

Habitat, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference into the Water Quality Control Plan for the Sacramento and San Joaquin River Basins specifies a range for sulfate of 250-500 mg/L assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531CR1047 (Mokelumne River -1047).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160551, Sulfates	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330373

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

WQX from the NWQMP for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 160551, Sulfates	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330303

Pollutant:

Sulfates

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-CARO-1047 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.


DECISION ID	160552	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

Pollutant:	Temperature, water
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 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. Sixteen lines of evidence are available in the administrative record to assess this pollutant. Pursuant to section 6.1.5.9 of the Listing Policy, this assessment utilized the upper limit of the optimal temperature range for rainbow trout for growth and completion of most life stages to interpret the narrative water quality objective for temperature. Zero of 194 samples exceeded the evaluation guideline applied to protect the COLD beneficial use. Zero of 100 samples exceeded the evaluation guideline for Fish Spawning and Fish Migration. However, the available data are insufficient to satisfy the Listing Policy requirements for spatial and temporal representation (sections 6.1.5.2 and 6.1.5.3). The surface water grab samples collected did not provide sufficient temporal and spatial representation to determine if temperature conditions experienced by aquatic life were within the optimal temperature range throughout the entire water column or the length of time temperature conditions may have exceeded the optimal temperature range. Available information for this waterbody-pollutant combination is insufficient to determine whether the aquatic beneficial use is supported. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available for this Integrated Report cycle indicating that standards are not met. This decision may be reevaluated in the next Integrated Report cycle as more data and information become available. Additional data and information may include information demonstrating that sample location(s) are representative of conditions throughout the waterbody, data from additional sampling locations, continuous monitoring data collected in the waterbody, waterbody-specific information on sensitive resident species, their life stage time frames, and the appropriate temperature thresholds necessary to support each life stage.

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:

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309649

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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 SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Temperature.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The natural receiving water temperature of intrastate waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Water Board that such alteration in temperature does not adversely affect beneficial uses (Sacramento-San Joaquin River Basin Plans.

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330463

Pollutant:

Temperature, water

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-CARO-1047 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

WQX from the NWQMP for the 2026 Integrated Report in Region 5

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330492

Pollutant:

Temperature, water

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:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309661

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Temperature.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309438

Pollutant:

Temperature, water

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 Ag Waiver data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 49 samples exceed the criterion for Water Temperature.

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 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:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Inland Fishes of California (1976)

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 2/11/2007-7/13/2010.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309604

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC111)

Temporal Representation:

The samples were collected between the dates of 2012-06-26 and 2012-06-26

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309606

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC111)

Temporal Representation:

The samples were collected between the dates of 2012-06-26 and 2012-06-26

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309609

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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 SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC111)

Temporal Representation:

The samples were collected between the dates of 2012-06-26 and 2012-06-26

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309647

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332906

Pollutant:

Temperature, water

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2017-03-21 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309652

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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 SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 13 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2012-06-26 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309654

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309656

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309658

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 13 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2012-06-26 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309659

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 14 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160552, Temperature, water	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309660

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Fish Migration

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 13 samples exceeded the water quality threshold for Temperature.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Inland Fishes of California (Moyle 1976) states that for rainbow trout the optimum range for growth and completion of most life stages is 13-21 degrees C (page 129).

Guideline Reference:

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2012-06-26 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):


DECISION ID	152344	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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 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 152344, Thiobencarb	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309631

Pollutant:

Thiobencarb

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

The evaluation guideline for Thiobencarb is the USEPA Aquatic Life Benchmark of 1 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2007-02-11 and 2008-09-16

Environmental Conditions:

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):


DECISION ID	166838	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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 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 166838, Total Dissolved Solids	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

346761

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the upper limit of the range for Total Dissolved Solids. Additionally, 0 of the 5 samples fall within the range, and 5 of 5 samples fall below the threshold.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference into the Water Quality Control Plan for the Sacramento and San Joaquin River Basins specifies a range for total dissolved solids of 500-1000 mg/L assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2010-12-07 and 2014-09-16

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	165288	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165288, Toxaphene	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309441

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:

Data Reference:

Data for Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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)

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 10/14/2008-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	171274	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(2024)
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. Previously considered water quality data was reevaluated according to new guidelines as part of this assessment. Lines of evidence have been replaced. 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:

Line of Evidence (LOE) for Decision ID 171274, Trifluralin	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

353273

Pollutant:

Trifluralin

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

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:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Trifluralin does not exceed 0.33 ug/L in the water column more than once every three years on average (Bower, et al. 2017).

Guideline Reference:

Water Quality Criteria Report for Trifluralin Phase III: Application of the pesticide water quality criteria methodology. Department of Environmental Toxicology University of California, Davis.

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2011-01-11 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition


DECISION ID	160567	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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

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:

Line of Evidence (LOE) for Decision ID 160567, Ziram	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

333089

Pollutant:

Ziram

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 San Joaquin County Delta Water Quality Coalition data for Mokelumne River, Lower (San Joaquin County, outside Delta Waterways) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Ziram. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

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 evaluation guideline for ziram is the USEPA Aquatic Life Benchmark of 1.4 ug/L for a fish (chronic).

Guideline Reference:

QAPP Reference for Irrigated Lands Regulatory Program

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2020-04-28 and 2020-04-28

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):


DECISION ID	165274	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165274, alpha-Endosulfan (Endosulfan 1)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309417

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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).

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 10/14/2008-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	165285	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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)(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. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:

Line of Evidence (LOE) for Decision ID 165285, beta-Endosulfan (Endosulfan 2)	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309395

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 Various Pollutants in San Joaquin and Delta Water Quality Coalition, 2004-2010.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Mokelumne River, Lower (in Delta Waterways, eastern portion) was collected at 1 monitoring site [Mokelumne River @ Bruella Rd - 531XMRABR]

Temporal Representation:

Data was collected over the time period 10/14/2008-12/8/2009.

Environmental Conditions:

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

QAPP Information:

Data for this line of evidence was collected as part of the Irrigated Lands Regulatory Program.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring by the San Joaquin County and Delta Water Quality Coalition.


DECISION ID	160549	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

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. Seventeen lines of evidence are available in the administrative record to assess this pollutant. Twenty-seven of the 276 samples exceeded the objectivefor COLD. Thirteen of the 99 samples exceed the objective for REC-1 and REC-2. 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. Twenty-seven of the 276 samples exceeded the objectivefor COLD. Thirteen of the 99 samples exceed the objective for REC-1 and REC-2. 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:

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309387

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Cold Freshwater Habitat

Aquatic Life Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

The San Joaquin Co Delta Water Quality Coalition collected 22 samples from August 2004 to September 2006. Two out of 22 samples were outside the acceptable range; both samples were lower than the acceptable range.

Data Reference:

Revised Draft of the 2007 Review of the Monitoring Data for the Irrigated Lands Regulatory Conditional Waiver Program

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH of water shall not be depressed below 6.5,raised above 8.5, or changed at any time more than 0.5 units from normal ambient pH.

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 two locations: Mokelumne River at Bruella Road and Mokelumne River at the Fish Hatchery.

Temporal Representation:

Sampling occurred from August 2004 to September 2006.

Environmental Conditions:

QAPP Information:

Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2003-0826) requirements (CVRWQCB, 2003)

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330165

Pollutant:

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-NRS_CA-10953 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2018-06-12 and 2018-06-12

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):

Habitat, Water data for the 2020/2022 integrated report in Region 5.

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309487

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed DFW_ABL_Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531CR1047)

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309488

Pollutant:

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:

Habitat, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531CR1047)

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309491

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Habitat, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531CR1047)

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309632

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 2 of 14 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309636

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 2 of 14 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309637

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 1 of 12 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309638

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309639

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 1 of 12 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309642

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309643

Pollutant:

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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531XMRABR)

Temporal Representation:

The samples were collected between the dates of 2010-09-07 and 2016-09-20

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 2.0)

QAPP Information Reference(s):

Quality Assurance Project Plan For Monitoring By The San Joaquin County & Delta Water Quality Coalition (Revision 3.0)

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring By the San Joaquin County & Delta Water Quality Coalition

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309645

Pollutant:

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 SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 2 of 14 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC512)

Temporal Representation:

The samples were collected between the dates of 2010-10-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

309646

Pollutant:

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 SWAMP RWB5 Monitoring data for Mokelumne River, Lower (in Delta Waterways, eastern portion) to determine beneficial use support and results are as follows: 1 of 12 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, Water data for the 2020/2022 integrated report in Region 5.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (531SJC110)

Temporal Representation:

The samples were collected between the dates of 2017-06-14 and 2017-10-10

Environmental Conditions:

QAPP Information:

SWAMP QAPrP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

332509

Pollutant:

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:

Field, Habitat, Toxicity, WQ from the Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 531XMRABR (Mokelumne River @ Bruella Rd).

Temporal Representation:

The samples were collected between the dates of 2017-03-21 and 2021-09-14

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 160549, pH	Region 5
Mokelumne River, Lower (San Joaquin County, outside Delta Waterways)

LOE ID:

330113

Pollutant:

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:

WQX from the NWQMP for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: pH should not be lower than 6.5 or higher than 8.5.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: NARS_WQX-CARO-1047 (Mokelumne River).

Temporal Representation:

The samples were collected between the dates of 2014-06-09 and 2014-06-09

Environmental Conditions:

QAPP Information:

SWAMP QAPrP

QAPP Information Reference(s):