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

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name:	San Joaquin River ( Mud Slough to Merced River)
Water Body ID:	CAR5357000020021002094621
Water Body Type:	River & Stream


DECISION ID	169241	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Reason for Delisting:	Flaws in original listing
Impairment from Pollutant or Pollution:	Pollution

Regional Board Conclusion:	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. The number of measured exceedances is less than the minimum number of exceedances needed to place the water segment on the section CWA section 303(d) List for toxicant pollutants (Tables 3.1 and 4.1 of the Listing Policy). Refer to the lines of evidence in this fact sheet for the data and information, sample counts and exceedances, quality assurance documentation, beneficial uses, and water quality objectives or numeric evaluation guidelines relied upon for this decision. 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. However, the exceedances of the evaluation guideline indicate that beneficial uses may be threatened based on a 303(d) listing developed prior to 2006. 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 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 this water segment-pollutant combination should not be placed 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 be removed from the section 303(d) list because the original basis for listing was flawed.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 169241, DDT (Dichlorodiphenyltrichloroethane)	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

4535

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Not Recorded

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

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:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	164607	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Group A Pesticides
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Reason for Delisting:	Flaws in original listing
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. This LOE documented an impairment and was made prior to 2006 and not held in an assessment database. 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. However, the exceedances of the evaluation guideline indicate that beneficial uses may be threatened. 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 fishing is occurring in this waterbody. 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. This LOE documented an impairment and was made prior to 2006 and not held in an assessment database. 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. However, the exceedances of the evaluation guideline indicate that beneficial uses may be threatened. 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 fishing is occurring in this waterbody. 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 be removed from the section 303(d) list because the original basis for listing was flawed.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 164607, Group A Pesticides	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

4537

Pollutant:

Group A Pesticides

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Not Recorded

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

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:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	165443	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Mercury
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Reason for Delisting:	Flaws in original listing
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 and 3.11 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.11 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 San Joaquin River ( Mud Slough to Merced River), 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 San Joaquin River ( Mud Slough to Merced River) and however it is unclear if the species sampled for LOE is included in the Statewide Health Advisory for mercury. The data was also not collected by SWAMP and it is unclear if the data was collected to monitor for pollutants in fish tissue to protect human health from consumption. Based on the readily available data and information, it is unclear if the COMM BU is existing. Beneficial use support for Commercial or recreational collection of fish, shellfish, or organisms will be reassessed in a future cycle, if more data are available. One lines of evidence are available in the administrative record to assess this pollutant. Zero of the Zero samples exceed the evaluation guideline for the COMM BU. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. LOE 4538 is a placeholder for a listing decision made before 2006. 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. However, the weight of evidence of the data and information indicate impairment is probable. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of zero samples exceeded the evaluation guideline for COMM BU and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. LOE 4538 is a placeholder for a listing made before 2006, however the data is unclear and it is not possible to determine if the COMM BU use is existing. 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:	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 165443, Mercury	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

4538

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Tissue

Matrix:

Tissue

Fraction:

Not Recorded

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

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:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	164097	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Selenium
Final Listing Decision:	Delist from 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)(2018)
Revision Status	Revised
Reason for Delisting:	Applicable WQS attained; reason for recovery unspecified
TMDL Name:	San Joaquin River Selenium
TMDL Project Code:	927
Date TMDL Approved by USEPA:	03/28/2002
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. Ten of the 336 samples exceeded the objective for WARM. 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. Ten of the 336 samples exceeded the objective for WARM and this does not exceed the allowable frequency listed in Table 4.1 of the Listing Policy. 4. The San Joaquin River Selenium TMDL has been approved by the Central Valley Water Board in 1997 and approved by USEPA on 03/28/2002. 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:

Line of Evidence (LOE) for Decision ID 164097, Selenium	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

2761

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Wildlife 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:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 164097, Selenium	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

70124

Pollutant:

Selenium

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:

SWAMP data indicates that 0 of 5 sample results exceed the criterion for Selenium.

Data Reference:

RWB5S Grasslands Bypass FY0708 FY0809

SWAMP Data:

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:

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:

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 San Joaquin River ( Mud Slough to Merced River) was collected at one monitoring site [ SJR @ Hills Ferry - 541STC512]

Temporal Representation:

Data was collected over the time period 7/19/2007-11/15/2007.

Environmental Conditions:

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

QAPP Information:

The SWAMP QAPP (2008) was followed.

QAPP Information Reference(s):

Surface Water Ambient Monitoring Program Quality Assurance Program Plan

Line of Evidence (LOE) for Decision ID 164097, Selenium	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

344256

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

286

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Waterboard staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 286 samples exceeded the water quality standard for Selenium

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for selenium in this water body is 0.005 mg/L (as a 4-day average).

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541SJRACI)

Temporal Representation:

The samples were collected between the dates of 2013-10-02 and 2021-12-08.

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 164097, Selenium	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6948

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

10 of the 45 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for Selenium.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Selenium levels for Mud Slough (north), and the San Joaquin River form Sack Dam to the mouth of the Merced River should not exceed 5 ug/L (4-day average), total concentration..

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 SJR @ Hills Ferry.

Temporal Representation:

The samples were collected from Jan 4 2001 to Sep 20 2007

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	164095	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Boron
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)(2020)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
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. Seven lines of evidence are available in the administrative record to assess pollutant. Five of the 46 samples exceed the 2 mg/L objective from March 15 - September 15 for Ag Supply. Zero of the five samples exceed the 0.7 mg/L objective for Ag Supply. Zero of the 229 samples exceed the 5.8 mg/L seven-day average objective for Ag Supply. Zero of the three samples exceed the 1.3 mg/L monthly objective for Ag Supply during critical water years, but was an ancillary LOE and not counted towards beneficial use support. Zero of the three samples exceed the 2 mg/L objective from March 15 - September 15 for Ag Supply, but was an ancillary LOE and not counted towards beneficial use support. Zero of two samples exceed the 5.8 mg/L seven-day average objective for Ag Supply, but was an ancillary LOE and not counted towards beneficial use support. 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. Five of the 46 samples exceed the 2 mg/L objective from March 15 - September 15 for Ag Supply and 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 164095, Boron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

59531

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:

Zero of the 5 samples collected exceeded the criterion for Boron.

Data Reference:

RWB5S Grasslands Bypass FY0708 FY0809

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Waters shall not contain chemical constituents in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

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

Evaluation Guideline:

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:

Samples were collected from the SJR @ Hills Ferry station (541STC512).

Temporal Representation:

Samples were collected on the following dates: 7/19/2007 8/16/2007 9/20/2007 10/18/2007 11/15/2007

Environmental Conditions:

QAPP Information:

SWAMP QAPP (2008).

QAPP Information Reference(s):

Surface Water Ambient Monitoring Program Quality Assurance Program Plan

Line of Evidence (LOE) for Decision ID 164095, Boron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

4534

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Agricultural Supply

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:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 164095, Boron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

344218

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:

Waterboard staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 5 of 46 samples exceeded the water quality standard for Boron

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for boron in this water body from March 15th through September 15th is 2 mg/L (as a monthly average).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541SJRACI)

Temporal Representation:

The samples were collected between the dates of 2014-03-21 and 2021-09-15. Samples collected outside of the seasonal dates (March 15th - September 15th) are not represented.

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 164095, Boron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

344209

Pollutant:

Boron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Agricultural Supply

Number of Samples:

229

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Waterboard staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 229 samples exceeded the water quality standard for Boron

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for boron in this water body is 5.8 mg/L (as a 7-day average).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541SJRACI)

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2021-12-08.

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 164095, Boron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

224356

Pollutant:

Boron

LOE Subgroup:

Ancillary Line of Evidence

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:

Water Board staff assessed San Joaquin River Restoration Program data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality standard for Boron.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for boron in this water body is 1.3 mg/L during critical water years, expressed as a monthly mean.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (SJRI_09)

Temporal Representation:

The samples were collected between the dates of 2010-09-01 and 2010-12-01

Environmental Conditions:

QAPP Information:

San Joaquin River Restoration Program

QAPP Information Reference(s):

The data included in this LOE does not have a QAPP, but was collected after the QAPP requirements had been developed, and thus was assessed as an ancillary line of evidence.

Line of Evidence (LOE) for Decision ID 164095, Boron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

220993

Pollutant:

Boron

LOE Subgroup:

Ancillary Line of Evidence

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:

Water Board staff assessed San Joaquin River Restoration Program data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Boron.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for boron in this water body is 5.8 mg/L expressed as a 7 day averaging period.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (SJRI_09)

Temporal Representation:

The samples were collected between the dates of 2010-09-01 and 2010-12-01

Environmental Conditions:

QAPP Information:

San Joaquin River Restoration Program

QAPP Information Reference(s):

The data included in this LOE does not have a QAPP, but was collected after the QAPP requirements had been developed, and thus was assessed as an ancillary line of evidence.

Line of Evidence (LOE) for Decision ID 164095, Boron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

224108

Pollutant:

Boron

LOE Subgroup:

Ancillary Line of Evidence

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for boron in this water body is 2 mg/L from 15 March through 15 September.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (SJRI_09)

Temporal Representation:

The samples were collected between the dates of 2010-09-01 and 2010-12-01

Environmental Conditions:

QAPP Information:

San Joaquin River Restoration Program

QAPP Information Reference(s):

The data included in this LOE does not have a QAPP, but was collected after the QAPP requirements had been developed, and thus was assessed as an ancillary line of evidence.


DECISION ID	158977	Region 5
San Joaquin River ( Mud Slough to Merced River)

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)(2018)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
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. Seven lines of evidence are available in the administrative record to assess pollutant. Seven of the 22 samples 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. Seven of the 22 samples exceed the objective for the aquatic life beneficial use, and 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 158977, Toxicity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

347485

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:

0 of the 1 samples collected by Grasslands Bypass Project for San Joaquin River ( Mud Slough to Merced River) 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: Pimephales promelas for Survival, Daphnia magna for Survival, Selenastrum capricornutum for Total Cell Count.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project 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 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:

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 monitoring site: 541SJRACI ( San Joaquin River at China Island (GBP) ).

Temporal Representation:

The samples were collected between the dates of 2015-10-13 and 2015-10-13.

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 158977, Toxicity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

22680

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 10 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:

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 Fisher's Exact test with 4-day acute-style toxicity tests.

Guideline Reference:

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

Spatial Representation:

Samples were collected from San Joaquin River at Hills Ferry.

Temporal Representation:

Samples were collected from October 2000 - November 2002

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 158977, Toxicity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

22679

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 12 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's Exact test with 6-day acute-style toxicity tests.

Guideline Reference:

Spatial Representation:

Samples were collected from San Joaquin River at Hills Ferry.

Temporal Representation:

Samples were collected from March 2004 - July 2006

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)

Line of Evidence (LOE) for Decision ID 158977, Toxicity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

22678

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 9 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's Exact test with 48-hour acute-style toxicity tests.

Guideline Reference:

Spatial Representation:

Samples were collected from San Joaquin River at Hills Ferry.

Temporal Representation:

Samples were collected from October 2001 - September 2002

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)

Line of Evidence (LOE) for Decision ID 158977, Toxicity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

22682

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 4 samples tested with Selenastrum capricornutum 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 t-test with 4-day chronic-style toxicity tests.

Guideline Reference:

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

Spatial Representation:

Samples were collected from San Joaquin River at Hills Ferry.

Temporal Representation:

Samples were collected from December 2005 - July 2006

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)

Line of Evidence (LOE) for Decision ID 158977, Toxicity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

22681

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:

7 of the 21 samples tested with Pimephales promelas were toxic and violated the narrative toxicity objective. Seven samples collected at Hills Ferry exhibited a statistically significant decrease in survival compared to the control. The sample dates and percent of control (in parentheses) are as follows:19 May 2005 (88)22 September 2005 (85)17 November 2005 (59)26 January 2006 (78)23 February 2006 (83)23 March 2006 (82)20 July 2006 (88)

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's Exact test with 7-day chronic-style toxicity tests.

Guideline Reference:

Spatial Representation:

Samples were collected from San Joaquin River at Hills Ferry.

Temporal Representation:

Samples were collected from March 2004 - July 2006

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)

Line of Evidence (LOE) for Decision ID 158977, Toxicity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

4539

Pollutant:

Unknown Toxicity

LOE Subgroup:

Toxicity

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:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	158967	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Chlorpyrifos
Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)(2018)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Name:	San Joaquin River Diazinon and Chlorpyrifos
TMDL Project Code:	209
Date TMDL Approved by USEPA:	01/01/2007
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. Two lines of evidence are available in the administrative record to assess pollutant. Zero of the one sample(s) exceed the objective for the WARM 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. Zero of the one sample(s) exceed the objective for the WARM beneficial use, and 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. 5. The San Joaquin River Diazinon and Chlorpyrifos TMDL was approved by the RWQCB in 2007 and subsequently approved by USEPA in 2007. The associated line of evidence is a placeholder to support a 303(d) listing decision made prior to 2006, before data and information were entered into a database.

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 158967, Chlorpyrifos	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

2762

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Wildlife 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:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 158967, Chlorpyrifos	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331336

Pollutant:

Chlorpyrifos

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Chlorpyrifos.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Chlorpyrifos is 0.015 ug/L (4-day average).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2018-03-06

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158969	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Diazinon
Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)(2018)
Revision Status	Revised
Sources:	A Source Unknown
TMDL Name:	San Joaquin River Diazinon and Chlorpyrifos
TMDL Project Code:	209
Date TMDL Approved by USEPA:	01/01/2007
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. One LOE is available in the record to assess this waterbody; however there is insufficient data to determine beneficial use support per the Listing Policy. This decision will be reassessed if additional data is submitted during a future cycle. The San Joaquin River Diazinon and Chlorpyrifos TMDL was approved by EPA in 2007. Based on the readily available information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination in the Water Quality Limited Segments Being Addressed portion of the 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 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 158969, Diazinon	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

2763

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Wildlife 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:

Placeholder reference 2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 158969, Diazinon	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331337

Pollutant:

Diazinon

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for Diazinon is 0.10 ug/L (4-day average).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

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

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158981	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	2, 4 DB / 4-(2,4-dichlorophenoxy) butyric acid
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	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 158981, 2, 4 DB / 4-(2,4-dichlorophenoxy) butyric acid	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331385

Pollutant:

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

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 2, 4 DB / 4-(2,4-dichlorophenoxy) butyric acid is the USEPA Aquatic Life Benchmark of 83 ug/L for a vascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2020-12-07 and 2020-12-07

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	167526	Region 5
San Joaquin River ( Mud Slough to Merced River)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. 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 167526, Ammonia	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6521

Pollutant:

Ammonia

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Zero of the 21 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation guideline for Ammonia.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

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:

Ammonia levels should not to exceed the calculated limit. Freshwater Aquatic Life Protection (Salmonid present) Criteria Maximum Concentration (CMC) (1-hour Average (mg N/L)) calculated based on the following formula: CMC = (0.275/(1 + 107.204-pH)) + (39.0/(1 + 10pH-7.204)) which incorporates pH (US EPA, 2005: Appendix C)

Guideline Reference:

1999 Update of Ambient Water Quality Criteria for Ammonia

Spatial Representation:

Samples were collected at SJR @ Hills Ferry.

Temporal Representation:

The samples were collected from Mar 31 1994 to Jan 29 2003.

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 167526, Ammonia	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

330737

Pollutant:

Nitrogen, ammonia (Total Ammonia)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and the results are as follows: 0 of the 32 samples exceeded the water quality threshold for Ammonia as N. Although a total of 33 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 Grasslands Bypass Project 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 (541SJRACI).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2021-11-22

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158963	Region 5
San Joaquin River ( Mud Slough to Merced River)

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)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. 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 158963, Arsenic	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

330773

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Arsenic.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved arsenic criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 150 ug/L. The conversion factor used to convert the total fraction criterion for arsenic to dissolved fraction criterion is 1. Therefore all data was considered to be representative of the dissolved fraction. (California Toxics Rule, 2000)

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:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2014-01-09

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 158963, Arsenic	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6522

Pollutant:

Arsenic

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:

None of the 16 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for Arsenic.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Arsenic criteria of 10ug/L (USEPA Primary MCL).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at SJR @ Hills Ferry.

Temporal Representation:

The samples were collected from Aug 29 2001 to Jun 26 2003

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	158985	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Bifenthrin
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 158985, Bifenthrin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

330824

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Bifenthrin. 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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:

Water Quality Criteria Report for Bifenthrin

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2019-06-03 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158964	Region 5
San Joaquin River ( Mud Slough to Merced River)

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)(2018)
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 158964, Cadmium	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6529

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

None of the 11 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 - Main-Stem San Joaquin River

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 San joaquin river at Hills Ferry

Temporal Representation:

The samples were collected between September 26, 2001 and November 20, 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 158964, Cadmium	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

330879

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved cadmium 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 2.2 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2014-01-09

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158965	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Carbaryl
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 158965, Carbaryl	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

330913

Pollutant:

Carbaryl

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 criterion for freshwater aquatic life for carbaryl is 2.1 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158966	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Chlorothalonil
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 158966, Chlorothalonil	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

330987

Pollutant:

Chlorothalonil

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 chlorothalonil is the USEPA Aquatic Life Benchmark of 0.6 ug/L for an invertebrate (chronic).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2018-03-06

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158968	Region 5
San Joaquin River ( Mud Slough to Merced River)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Two of the 55 samples exceed the criteria for the WARM beneficial 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. Two of the 55 samples exceed the criteria for the WARM beneficial 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:

Line of Evidence (LOE) for Decision ID 158968, Copper	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6532

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

None of the 50 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for Copper.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at SJR @ Hills Ferry.

Temporal Representation:

The samples were collected from Oct 29 1992 to Nov 20 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 158968, Copper	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331099

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 2 of 5 samples exceeded the water quality threshold for Copper.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2020-01-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158990	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Cyfluthrin
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 158990, Cyfluthrin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331132

Pollutant:

Cyfluthrin

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 2 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, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158991	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Cyhalothrin, Lambda
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 158991, Cyhalothrin, Lambda	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331682

Pollutant:

Cyhalothrin, Lambda

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 3 samples were collected, 3 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158986	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Cypermethrin
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 158986, Cypermethrin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331190

Pollutant:

Cypermethrin

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2019-06-03 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158987	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Dimethoate
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 158987, Dimethoate	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331440

Pollutant:

Dimethoate

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Dimethoate.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for an invertebrate (chronic).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-05-21

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158970	Region 5
San Joaquin River ( Mud Slough to Merced River)

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

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 158970, Diuron	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331454

Pollutant:

Diuron

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2019-01-24 and 2020-12-07

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158992	Region 5
San Joaquin River ( Mud Slough to Merced River)

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 158992, Esfenvalerate/Fenvalerate	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331517

Pollutant:

Esfenvalerate/Fenvalerate

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2019-01-24 and 2020-01-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158971	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Glyphosate
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 158971, Glyphosate	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331590

Pollutant:

Glyphosate

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Glyphosate.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2019-01-24 and 2021-03-16

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158993	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Hexazinone
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 158993, Hexazinone	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331632

Pollutant:

Hexazinone

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 hexazinone is the USEPA Aquatic Life Benchmark of 7 ug/L for a nonvascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2020-01-03 and 2020-01-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158982	Region 5
San Joaquin River ( Mud Slough to Merced River)

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 158982, Imidacloprid	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331652

Pollutant:

Imidacloprid

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 3 samples were collected, 3 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 Grasslands Bypass Project 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 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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158972	Region 5
San Joaquin River ( Mud Slough to Merced River)

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)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. 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 158972, Lead	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331741

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved lead 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 2.5 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2014-01-09

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 158972, Lead	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6535

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Zero of the 51 samples collected by the Surface Water Ambient Monitoring Program exceeded the calculated CTR CMC for dissolved lead

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

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 San Joaquin River at Hills Ferry

Temporal Representation:

The samples were collected between October 29, 1992 and November 20, 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	158973	Region 5
San Joaquin River ( Mud Slough to Merced River)

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

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 158973, Malathion	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331754

Pollutant:

Malathion

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 2 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, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-05-21

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158983	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Methomyl
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 158983, Methomyl	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331809

Pollutant:

Methomyl

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 is 0.5 ug/L (4-day average). (CDFG, 1996)

Guideline Reference:

OPP Pesticide Ecotoxicity Database.

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2019-05-21 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	164096	Region 5
San Joaquin River ( Mud Slough to Merced River)

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 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 164096, Molybdenum	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6541

Pollutant:

Molybdenum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

0 of the 59 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation objective for Molybdenum.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

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 SJR @ Hills Ferry.

Temporal Representation:

The samples were collected from Oct 25 1995 to Nov 16 2006

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 164096, Molybdenum	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

224053

Pollutant:

Molybdenum

LOE Subgroup:

Ancillary Line of Evidence

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:

Water Board staff assessed San Joaquin River Restoration Program data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality standard for Molybdenum.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for molybdenum in this water body is 0.019 mg/L expressed as a monthly mean.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (SJRI_09)

Temporal Representation:

The samples were collected between the dates of 2010-09-01 and 2010-12-01

Environmental Conditions:

QAPP Information:

San Joaquin River Restoration Program

QAPP Information Reference(s):

The data included in this LOE does not have a QAPP, but was collected after the QAPP requirements had been developed, and thus was assessed as an ancillary line of evidence.

Line of Evidence (LOE) for Decision ID 164096, Molybdenum	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

344245

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:

Waterboard staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 61 samples exceeded the water quality standard for Molybdenum

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for molybdenum in this water body is 0.05 mg/L (as a 7-day average).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541SJRACI)

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2021-11-22.

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 164096, Molybdenum	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

344238

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:

Waterboard staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 59 samples exceeded the water quality standard for Molybdenum

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Basin Plan objective for molybdenum in this water body is 0.019 mg/L (as a monthly average).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541SJRACI)

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2021-11-22.

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 164096, Molybdenum	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

70109

Pollutant:

Molybdenum

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

SWAMP data indicates that 0 of 5 sample results exceed the criterion for Molybdenum.

Data Reference:

RWB5S Grasslands Bypass FY0708 FY0809

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The maximum concentration of molybdenum in Salt Slough, Mud Slough (north), San Joaquin River from Sack Dam to the mouth of Merced River, is 50 ug/L. (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 San Joaquin River ( Mud Slough to Merced River) was collected at one monitoring site [ SJR @ Hills Ferry - 541STC512]

Temporal Representation:

Data was collected over the time period 7/19/2007-11/15/2007.

Environmental Conditions:

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

QAPP Information:

The SWAMP QAMP (2002) was used for data before Septemper 1, 2008 and SWAMP QAPP (2008) was thereafter.

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)

QAPP Information Reference(s):

Surface Water Ambient Monitoring Program Quality Assurance Program Plan


DECISION ID	158974	Region 5
San Joaquin River ( Mud Slough to Merced River)

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)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. 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:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 158974, Nickel	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331865

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved nickel 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 52 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2014-01-09

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 158974, Nickel	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6544

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Zero of the 51 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 - Main-Stem San Joaquin River

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 San Joaquin River at Hills Ferry

Temporal Representation:

The samples were collected between October 29, 1992, and November 20, 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	158984	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Oryzalin
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 158984, Oryzalin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331983

Pollutant:

Oryzalin

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 oryzalin is the USEPA Aquatic Life Benchmark of 13 ug/L for a vascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-12-10 and 2018-12-10

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158988	Region 5
San Joaquin River ( Mud Slough to Merced River)

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 158988, Oxyfluorfen	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

331994

Pollutant:

Oxyfluorfen

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Oxyfluorfen.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-12-10 and 2021-03-16

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158975	Region 5
San Joaquin River ( Mud Slough to Merced River)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Seven lines of evidence are available in the administrative record to assess this pollutant. Eight of 370 samples exceed the criteria for aquatic life and one of eight samples exceed the objective for fish spawning. 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. Eight of 370 samples exceed the criteria for aquatic life and one of eight samples exceed the objective for fish spawning 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 158975, Oxygen, Dissolved	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

23297

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:

Seventy-six samples were taken from the San Joaquin River between 2001 and 2006. Five of the seventy-six samples fell below the Water Quality Objective for minimum dissolved oxygen content in surface water.

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:

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 San Joaquin River at Hill Ferry in Stanislaus County.

Temporal Representation:

Samples were collected between June 2001 and March 2006. Samples were collected at bi-monthly and monthly intervals.

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 158975, Oxygen, Dissolved	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

70112

Pollutant:

Oxygen, Dissolved

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 to determine beneficial use support: One of 3 sample results exceed the criterion for Oxygen, Dissolved.

Data Reference:

Data for Various Pollutants in East San Joaquin, 2004-2009.

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 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 was collected at one monitoring site [SJR @ Hills Ferry-541STC512].

Temporal Representation:

Data was collected on three dates in 2010.

Environmental Conditions:

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

QAPP Information:

The Quality Assurance Project Plan by the East San Joaquin Water Quality Coalition, Revision 1.0 was followed.

QAPP Information Reference(s):

Quality Assurance Project Plan by the East San Joaquin Water Quality Coalition, Revision 1.0.

Line of Evidence (LOE) for Decision ID 158975, Oxygen, Dissolved	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

332109

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

281

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 2 of 281 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The minimum dissolved oxygen concentration for waters designated as WARM is 5.0 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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2021-12-08

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652

Line of Evidence (LOE) for Decision ID 158975, Oxygen, Dissolved	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

70111

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

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 Ag Waiver data to determine beneficial use support: One of 3 sample results exceed the criterion for Oxygen, Dissolved.

Data Reference:

Data for Various Pollutants in East San Joaquin, 2004-2009.

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 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 was collected at one monitoring site [SJR @ Hills Ferry-541STC512].

Temporal Representation:

Data was collected on three dates in 2010.

Environmental Conditions:

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

QAPP Information:

The Quality Assurance Project Plan by the East San Joaquin Water Quality Coalition, Revision 1.0 was followed.

QAPP Information Reference(s):

Quality Assurance Project Plan by the East San Joaquin Water Quality Coalition, Revision 1.0.

Line of Evidence (LOE) for Decision ID 158975, Oxygen, Dissolved	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

70110

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

SWAMP data indicates that 0 of 5 sample results exceed the criterion for Oxygen, Dissolved.

Data Reference:

RWB5S SJR Trends FY0708 FY0809

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:

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 San Joaquin River ( Mud Slough to Merced River) was collected at one monitoring site [ SJR @ Hills Ferry - 541STC512]

Temporal Representation:

Data was collected over the time period 7/19/2007-11/15/2007.

Environmental Conditions:

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

QAPP Information:

The SWAMP QAPP (2008) was followed.

QAPP Information Reference(s):

Surface Water Ambient Monitoring Program Quality Assurance Program Plan

Line of Evidence (LOE) for Decision ID 158975, Oxygen, Dissolved	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

329997

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm 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 USGS California Water Science Center data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 0 of 5 samples exceeded the water quality threshold for Oxygen, Dissolved.

Data Reference:

WQX from the NWQMP 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 WARM is 5.0 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: USGS-11273400 (SAN JOAQUIN R AB MERCED R NR NEWMAN CA).

Temporal Representation:

The samples were collected between the dates of 2014-08-12 and 2016-10-03

Environmental Conditions:

QAPP Information:

QAPP for USGS Data Collected during the 2026 Integrated Report Cycle

QAPP Information Reference(s):

QAPP for USGS Data Collected during the 2026 Integrated Report Cycle

Line of Evidence (LOE) for Decision ID 158975, Oxygen, Dissolved	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

59520

Pollutant:

Oxygen, Dissolved

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 5 samples collected exceeded the objective.

Data Reference:

RWB5S SJR Trends FY0708 FY0809

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved oxygen concentrations shall not be reduced below the following minimum levels at any time: Waters designated COLD 7.0 mg/l

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the SJR @ Hills Ferry station (541STC512).

Temporal Representation:

Samples were collected on the following dates: 7/19/2007 8/16/2007 9/20/2007 10/18/2007 11/15/2007

Environmental Conditions:

QAPP Information:

SWAMP QAPP

QAPP Information Reference(s):

Surface Water Ambient Monitoring Program Quality Assurance Program Plan


DECISION ID	158989	Region 5
San Joaquin River ( Mud Slough to Merced River)

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 158989, Pendimethalin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

332310

Pollutant:

Pendimethalin

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2019-01-24 and 2020-12-07

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158994	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Permethrin
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 158994, Permethrin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

332339

Pollutant:

Permethrin

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:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 3 samples were collected, 3 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-06-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158996	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Pyraclostrobin
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 158996, Pyraclostrobin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

332545

Pollutant:

Pyraclostrobin

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 pyraclostrobin is the USEPA Aquatic Life Benchmark of 1.5 ug/L for a nonvascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2021-03-16 and 2021-03-16

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158980	Region 5
San Joaquin River ( Mud Slough to Merced River)

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:

Line of Evidence (LOE) for Decision ID 158980, Pyrethroids	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

332625

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) 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 5 samples were collected, 5 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2020-01-03

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158995	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Tebuconazole
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 158995, Tebuconazole	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

332881

Pollutant:

Tebuconazole

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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 tebuconazole is the USEPA Aquatic Life Benchmark of 11 ug/L for a fish (chronic).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2021-03-16 and 2021-03-16

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158978	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Trifluralin
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 158978, Trifluralin	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

333037

Pollutant:

Trifluralin

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:

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2018-03-06 and 2019-05-21

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158979	Region 5
San Joaquin River ( Mud Slough to Merced River)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One of 50 samples, reported in the dissolved fraction, exceed the criteria for WARM. 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. One of 50 samples, reported in the dissolved fraction, exceed the criteria for WARM 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:

Line of Evidence (LOE) for Decision ID 158979, Zinc	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6547

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

One of the 47 samples collected by the Surface Water Ambient Monitoring Program exceeded the calculauted CTR CMC for dissolved zinc. The sample that exceeded the objective was collected from the San Joaquin River at Hill's Ferry and had a dissolved zinc concentration of 230ug/L

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

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 San Joaquin River at Hills Ferry

Temporal Representation:

The samples were collected between October 29, 1992, to November 20, 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 158979, Zinc	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

333079

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm 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 Grasslands Bypass Project for the 2026 Integrated Report in Region 5

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The dissolved zinc 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 120 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2014-01-09

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	158976	Region 5
San Joaquin River ( Mud Slough to Merced River)

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)(2018)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Five of 539 water samples exceeded the objective for WARM. Zero of five samples exceeded 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. Five of 539 water samples exceeded the objective for WARM. Zero of five samples exceeded the objective for REC-1. 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 158976, pH	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

23299

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

292

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

The Central Valley Regional Water Quality Control Board Surface Water Ambient Monitoring Program collected 292 samples from October 1995 to March 2006. Two out of 292 samples were outside the acceptable range; one sample was higher than the acceptable range and one sample was lower than the acceptable range.

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:

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 San Joaquin River at Hills Ferry.

Temporal Representation:

Sampling occurred from October 1995 to March 2006.

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)

Line of Evidence (LOE) for Decision ID 158976, pH	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

70123

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:

SWAMP data indicates that 0 of 5 sample results exceed the criterion for pH.

Data Reference:

RWB5S SJR Trends FY0708 FY0809

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

pH should not be lower than 6.5 or higher than 8.5. (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:

Draft Guidance for Fresh Water Beaches. Last Update: May 8, 2006. Initial Draft: November 1997. California Department of Public Health.

Spatial Representation:

Data for this line of evidence for San Joaquin River ( Mud Slough to Merced River) was collected at one monitoring site [ SJR @ Hills Ferry - 541STC512]

Temporal Representation:

Data was collected over the time period 7/19/2007-11/15/2007.

Environmental Conditions:

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

QAPP Information:

The SWAMP QAPP (2008) was followed.

QAPP Information Reference(s):

Surface Water Ambient Monitoring Program Quality Assurance Program Plan

Line of Evidence (LOE) for Decision ID 158976, pH	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

330067

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm 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:

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: USGS-11273400 (SAN JOAQUIN R AB MERCED R NR NEWMAN CA).

Temporal Representation:

The samples were collected between the dates of 2014-08-12 and 2016-10-03

Environmental Conditions:

QAPP Information:

QAPP for USGS Data Collected during the 2026 Integrated Report Cycle

QAPP Information Reference(s):

QAPP for USGS Data Collected during the 2026 Integrated Report Cycle

Line of Evidence (LOE) for Decision ID 158976, pH	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

332385

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

242

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Grasslands Bypass Project data for San Joaquin River ( Mud Slough to Merced River) to determine beneficial use support and results are as follows: 3 of 242 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Toxicity, WQ from the Grasslands Bypass Project 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: 541SJRACI (San Joaquin River at China Island (GBP)).

Temporal Representation:

The samples were collected between the dates of 2013-11-04 and 2021-12-08

Environmental Conditions:

QAPP Information:

GBP QAPP - Grasslands Bypass Project

QAPP Information Reference(s):

SWRCB - Region5 - GBP QAPP - Grasslands Bypass Project - 402652


DECISION ID	168909	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Specific Conductivity
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
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. One line of evidence is available in the administrative record to assess this pollutant. Five thousand seven hundred twenty-four of the 7,544 samples exceed the objective for AGR. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Five thousand seven hundred twenty-four of the 7,544 samples exceed the objective for AGR and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 168909, Specific Conductivity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

31459

Pollutant:

Electrical Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Agricultural Supply

Number of Samples:

7544

Number of Exceedances:

5724

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

USEPA has carefully reviewed SWAMP data and found for this segment, there were 7544 samples to assess the AGR beneficial use objective. Of those 7544 samples, 5724 samples exceeded the AGR beneficial use objective.

Data Reference:

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

USEPA Region 9 data summary for addition of electrical conductivity and total dissolved solids to California 2010 303(d) list for some Central Valley - Region 5 water bodies

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

For the Agricultural (AGR) beneficial use the Basin Plan "recommended" maximum 30-day running average for April 1 to August 31 is 0.7 uS/mm and for Sept 1 - March 31 is 1.0 uS/mm

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 in the San Joaquin River at Patterson Fishing Access (Lat 37 29 52, Long 121 04 54) and Hills Ferry Bridge (Lat 37 20 33, Long 120 58 33) by SWAMP.

Temporal Representation:

Samples were collected weekly from October 1995 to October 2006.

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	132015	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Temperature, water
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
TMDL Priority:	Low
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. Four lines of evidence are available in the administrative record to assess this pollutant. Of these lines of evidence four were based on continuous monitoring data. Continuous temperature data were used as the primary source of evidence for this assessment. A rolling 7-Day Average of Daily Maximum (7DADM) was calculated for all available data and a 7DADM is evaluated as a single sample. In the absence of natural or historical temperature data, the samples were compared against USEPA Region 10 recommended temperature requirements for each appropriate salmonid life stage present in the waterbody segment (Listing Policy Section 6.1.5.9). A total of 793 of 1,415 samples exceed the evaluation guideline (USEPA 2003) applied to protect the migration (MIGR) freshwater habitat beneficial use. The evaluation guideline was applied during the smolt migration (20 degrees Celsius between March 15 – June 15) and adult migration (20 degrees Celsius between September 1 – December 31) salmonid life stages. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Listing Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Listing Policy. 3. 793 of 1,415 samples exceed the MIGR evaluation guideline for the 7DADM and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

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 be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

Line of Evidence (LOE) for Decision ID 132015, Temperature, water	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

232784

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Migration

Number of Samples:

491

Number of Exceedances:

263

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data collected hourly from 2008 through 2013 at station SJRNW (SJR, Downstream of Newman Wasteway). The data was provided by staff at the San Joaquin River Restoration Project. Only data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric. The 7-DADM temperatures were computed for the contiguous 7-day periods available during this time frame. The 7-day average of maximum daily temperature exceeded the evaluation guideline during 263 of the 491 7-day periods.

Data Reference:

Continuous temperature data provided by CDFW's San Joaquin River Restoration Project.

SWAMP Data:

Non-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.

Objective/Criterion Reference:

Evaluation Guideline:

A 7-day average of daily maximum (7-DADM) temperature of 20 degrees Celsius is recommended by the USEPA for waterbodies that are used almost exclusively for migration during the period of summer maximum temperatures to protect migrating juveniles and adults from lethal temperatures (USEPA, 2003). This evaluation guideline was applied to both the smolt (March 15 - June 15) and adult (September 1 - December 31) migration periods.

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. U.S. Environmental Protection Agency Region 10 Office of Water, Seattle, WA.

Spatial Representation:

Data collected from San Joaquin River Restoration Project Station SJRNW (SJR, Downstream of Newman Wasteway).

Temporal Representation:

Data collected hourly from 2008 through 2013. Data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric.

Environmental Conditions:

QAPP Information:

The data were collected by the California Department of Fish and Wildlife as part of the San Joaquin River Restoration Project and are deemed by the CDFW to be reliable and of sound quality. Information about the monitoring equipment used is available in the reference.

QAPP Information Reference(s):

San Joaquin River Restoration Program Stream Temperature Monitoring Study Standard Operating Procedures (SOPs) by the California Department of Fish and Wildlife.

Line of Evidence (LOE) for Decision ID 132015, Temperature, water	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

232865

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Migration

Number of Samples:

429

Number of Exceedances:

247

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data collected hourly from 2009 through 2014 at station SJRHF (SJR @ Hills Ferry). The data was provided by staff at the San Joaquin River Restoration Project. Only data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric. The 7-DADM temperatures were computed for the contiguous 7-day periods available during this time frame. The 7-day average of maximum daily temperature exceeded the evaluation guideline during 247 of the 429 7-day periods.

Data Reference:

Continuous temperature data provided by CDFW's San Joaquin River Restoration Project.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. U.S. Environmental Protection Agency Region 10 Office of Water, Seattle, WA.

Spatial Representation:

Data collected from San Joaquin River Restoration Project Station SJRHF (SJR @ Hills Ferry).

Temporal Representation:

Data collected hourly from 2009 through 2014. Data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

San Joaquin River Restoration Program Stream Temperature Monitoring Study Standard Operating Procedures (SOPs) by the California Department of Fish and Wildlife.

Line of Evidence (LOE) for Decision ID 132015, Temperature, water	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

232782

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Migration

Number of Samples:

335

Number of Exceedances:

239

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data collected hourly from 2017 through 2019 at station SJRMUDSDS (SJR, Downstream of Mud Slough). The data was provided by staff at the San Joaquin River Restoration Project. Only data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric. The 7-DADM temperatures were computed for the contiguous 7-day periods available during this time frame. The 7-day average of maximum daily temperature exceeded the evaluation guideline during 239 of the 335 7-day periods.

Data Reference:

Continuous temperature data provided by CDFW's San Joaquin River Restoration Project.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. U.S. Environmental Protection Agency Region 10 Office of Water, Seattle, WA.

Spatial Representation:

Data collected from San Joaquin River Restoration Project Station SJRMUDSDS (SJR, Downstream of Mud Slough).

Temporal Representation:

Data collected hourly from 2017 through 2019. Data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

San Joaquin River Restoration Program Stream Temperature Monitoring Study Standard Operating Procedures (SOPs) by the California Department of Fish and Wildlife.

Line of Evidence (LOE) for Decision ID 132015, Temperature, water	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

232783

Pollutant:

Temperature, water

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Fish Migration

Number of Samples:

160

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data collected hourly from 2018 through 2019 at station SJRNEWDS (SJR, Downstream of Newman Wasteway). The data was provided by staff at the San Joaquin River Restoration Project. Only data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric. The 7-DADM temperatures were computed for the contiguous 7-day periods available during this time frame. The 7-day average of maximum daily temperature exceeded the evaluation guideline during 44 of the 160 7-day periods.

Data Reference:

Continuous temperature data provided by CDFW's San Joaquin River Restoration Project.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards. EPA 910-B-03-002. U.S. Environmental Protection Agency Region 10 Office of Water, Seattle, WA.

Spatial Representation:

Data collected from San Joaquin River Restoration Project Station SJRNEWDS (SJR, Downstream of Newman Wasteway).

Temporal Representation:

Data collected hourly from 2018 through 2019. Data from the smolt migration period, March 15 through June 15, and the adult migration period, September 1 through December 31, were assessed for this metric.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

San Joaquin River Restoration Program Stream Temperature Monitoring Study Standard Operating Procedures (SOPs) by the California Department of Fish and Wildlife.


DECISION ID	69946	Region 5
San Joaquin River ( Mud Slough to Merced River)

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)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data or information was available during the 2014 Integrated Report cycle to reassess this water body segment and pollutant. The decision has not changed. This pollutant was originally considered for listing under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Data is available from one line of evidence for this pollutant. None of 22 water sample results exceed 100 mg/L (USEPA National Ambient Water Quality Objective). Based on the readily available data and information, the weight of evidence indicates that there is not sufficient justification for placing this water segment-pollution combination on the section 303(d) list. The recommendation is based on staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of 22 available concentrations exceed the evaluation guideline for the Warm Freshwater Habitat beneficial use, and this does not exceed the allowable frequency using Table 3.1 of the Listing Policy. Table 3.1 of the listing policy recommends listing if a sample size of 22 has 2 or more samples that exceed the evaluation criteria. 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:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data or information was available during the 2014 Integrated Report cycle to reassess this water body segment and pollutant. The decision has not changed.

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 69946, Nitrate as Nitrate (NO3)	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

6545

Pollutant:

Nitrate as Nitrate (NO3)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

0 of the 22 samples collected by the Surface Water Ambient Monitoring Program exceeded the evaluation guideline for Nitrate-N.

Data Reference:

San Joaquin River SWAMP Monitoring Data - Main-Stem San Joaquin River

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 SJR @ Hills Ferry.

Temporal Representation:

The samples were collected from Jul 27 1994 to Dec 18 2002

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	77789	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Electrical Conductivity
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Sources:	A Source Unknown
TMDL Priority:	Low
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 4.2 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. 5724 of the 7544 samples exceed the criteria for AG. 632 of the 848 samples exceed the criteria 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. 5724 of the 7544 samples exceed the criteria for AG and this exceeds the allowable frequency listed in Table 4.2 of the Listing Policy. 4. 632 of the 848 samples exceed the criteria for MUN and this exceeds the allowable frequency listed in Table 4.2 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 met.

Regional Board Decision Recommendation:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.

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 77789, Electrical Conductivity	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

31459

Pollutant:

Electrical Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Agricultural Supply

Number of Samples:

7544

Number of Exceedances:

5724

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

USEPA Region 9 data summary for addition of electrical conductivity and total dissolved solids to California 2010 303(d) list for some Central Valley - Region 5 water bodies

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

For the Agricultural (AGR) beneficial use the Basin Plan "recommended" maximum 30-day running average for April 1 to August 31 is 0.7 uS/mm and for Sept 1 - March 31 is 1.0 uS/mm

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 in the San Joaquin River at Patterson Fishing Access (Lat 37 29 52, Long 121 04 54) and Hills Ferry Bridge (Lat 37 20 33, Long 120 58 33) by SWAMP.

Temporal Representation:

Samples were collected weekly from October 1995 to October 2006.

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	73641	Region 5
San Joaquin River ( Mud Slough to Merced River)

Pollutant:	Indicator Bacteria
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Sources:	A Source Unknown
TMDL Priority:	Low
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One lines of evidence are available in the administrative record to assess this pollutant. Eleven of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Eleven of 32 samples exceed the E. Coli objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.

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 73641, Indicator Bacteria	Region 5
San Joaquin River ( Mud Slough to Merced River)

LOE ID:

23298

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:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

The Central Valley Regional Water Quality Control Board Surface Water Ambient Monitoring Program collected 32 samples from July 2002 to March 2006. Eleven out of the 32 samples exceeded the evaluation 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:

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

Objective/Criterion Reference:

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:

Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002

Evaluation Guideline:

The USEPA E. Coli objective of 235/100 mL in any single sample (USEPA 1986).

Guideline Reference:

Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002

Spatial Representation:

Samples were collected at San Joaquin River at Hills Ferry.

Temporal Representation:

Sampling occurred from July 2002 to March 2006.

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):

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)