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

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name:	Poso Slough
Water Body ID:	CAR5412000020070511112656
Water Body Type:	River & Stream


DECISION ID	73470	Region 5
Poso Slough

Pollutant:	Toxicity
Final Listing Decision:	Do Not Delist from 303(d) list (being addressed with action other than TMDL)
Last Listing Cycle's Final Listing Decision:	Do Not Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Revised
Sources:	A Source Unknown
Expected Attainment Date:	2024
Implementation Action Other than TMDL:	This listing is being addressed through the implementation of the Central Valley Water Board Irrigated Lands Regulatory program (ILRP), General Order R5-2014-0002, for the Westside San Joaquin River Watershed Coalition (Coalition). The Coalition has two active management plans for toxicity that were developed prior to the General Order. The Westside San Joaquin River Watershed Coalition Management Plan ¿ General Approach was developed in 2008 and the Westside San Joaquin River Watershed Coalition Focused Watershed Management Plan III Poso Slough & Salt Slough was developed in 2011. Both management plans stated the sources of toxicity identify agricultural practices as a significant contributor and require ongoing monitoring of the water bodies to assess progress at meeting water quality standards. Agricultural management practices to reduce toxicity in surface water include integrated pest management programs, conversion to high-efficiency irrigation systems, vegetation management and water management practices. The management plans are required to be updated until water quality criteria are achieved.
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for removal from the section 303(d) list under sections 3.1 and 3.6 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 three sediment samples exhibited statistically significant toxicity to Hyalella azteca (amphipod species). Based on the readily available data and information, the weight of evidence indicates that there is insufficient justification in favor of removing this water segment-pollutant combination from the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of three sediment samples exhibited statistically significant toxicity to Hyalella Azteca, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. A water quality management plan for toxicity for Poso Slough was approved by the Central Valley Water Board Irrigated Lands Regulatory Program. Management practices were implemented by growers to address toxicity exceedances. 5. Poso Slough was originally identified as impaired by toxicity in 2014. 6. 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 removed from 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 73470, Toxicity	Region 5
Poso Slough

LOE ID:

22978

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Cold Freshwater Habitat

Aquatic Life Use:

Cold Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Two of the three samples tested with Hyalella azteca were toxic. Two samples collected at Poso Slough at Hudson exhibited a statistically significant decrease in growth compared to the control. The sample dates and percent of control (in parentheses) are as follows:25 March 2005 (29)20 August 2005 (0)Toxicity observations were associated with pyrethroid and organophosphate pesticides. LC50s for sediment-bound pyrethroids were used in this study as toxicity threshold benchmarks in a Toxic Unit (TU) analysis normalized to organic carbon content. The TU analysis of Poso Slough sediment samples demonstrated that the sample with significant bioassay mortality collected on 3/25/05 had 2.96 TUs of pyrethroid pesticides (0.47 TU bifenthrin, 2.16 TU lambda-cyhalothrin, 0.05 TU permethrin, and 0.28 TU cyfluthrin) and 0.11 TU of chlorpyrifos. The other sediment sample with significant bioassay mortality was collected on 8/20/05 and had 0.00 TUs of pyrethroids and 0.79 TUs of chlorpyrifos. A sample was also collected on 11/20/05, which did not have statistically significant bioassay mortality. The 11/20/05 sample contained 0.22 TUs of pyrethroids and 0.59 TUs of chlorpyrifos. In summary, only one of the toxic sediment samples had concentrations of pyrethroids above 1 TU. Chlorpyrifos was not observed above 1 TU.

Data Reference:

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

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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, 2004)

Objective/Criterion Reference:

Water Quality Control Plan for the Tulare Lake Basin Second Edition. rev. Jan 2004

Evaluation Guideline:

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

Guideline Reference:

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

Spatial Representation:

Samples were collected from one location on Poso Slough in Fresno County. Sediment toxicity was observed from two samples.

Temporal Representation:

Samples were collected from March 2005 to August 2005.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 73470, Toxicity	Region 5
Poso Slough

LOE ID:

69159

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Two samples were collected to evaluate sediment toxicity. One of the samples exhibited significant toxicity. The toxicity tests included survival of Hyalella azteca. One sample can have multiple toxicity test results but will be counted only once. One sample is defined as being collected on the same day at the same location with the same lab sample id (if provided).

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in, human, plant, animal, or aquatic life. Region 5 Basin Plan.

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at Poso Slough at Indiana Ave.

Temporal Representation:

The samples were collected in March and September 2008.

Environmental Conditions:

QAPP Information:

Collected under the Monitoring and Reporting Program Plans for the Westside Water Quality Coalition.

QAPP Information Reference(s):


DECISION ID	159167	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159167, 2,4-D (2,4-Dichlorophenoxy acetic acid)	Region 5
Poso Slough

LOE ID:

331380

Pollutant:

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

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Dichlorophenoxyacetic Acid, 2,4-.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for 2, 4-D incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.07 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; Fifth Edition. Revised May 2018 (with approved amendments)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2019-02-14 and 2021-02-09

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	117421	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117421, Aldicarb	Region 5
Poso Slough

LOE ID:

69076

Pollutant:

Aldicarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Aldicarb.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117421, Aldicarb	Region 5
Poso Slough

LOE ID:

185873

Pollutant:

Aldicarb

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 60 samples exceeded the water quality threshold for Aldicarb.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for aldicarb incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 3 ug/L

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117422	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117422, Aldrin	Region 5
Poso Slough

LOE ID:

69083

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Aldrin.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The CTR objective for aldrin to protect human health from the consumption of water and organisms is 0.00013 ug/L.

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117422, Aldrin	Region 5
Poso Slough

LOE ID:

185972

Pollutant:

Aldrin

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Aldrin. Although a total of 54 samples were collected, 54 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Aldrin criteria for the protection of human health from the consumption of water and organisms is 0.00013 ug/L (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 (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	159160	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159160, Arsenic	Region 5
Poso Slough

LOE ID:

69086

Pollutant:

Arsenic

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 1 of 7 samples exceed the criterion for Arsenic.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for arsenic is 0.010 mg/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 159160, Arsenic	Region 5
Poso Slough

LOE ID:

186303

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 4 of 60 samples exceeded the water quality threshold for Arsenic.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for arsenic incorporated by reference in the Basin Plan is 0.010 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159160, Arsenic	Region 5
Poso Slough

LOE ID:

330788

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 3 of 45 samples exceeded the water quality threshold for Arsenic.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for arsenic incorporated by reference in the Basin Plan is 0.010 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-03-02 and 2022-02-08

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	117398	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117398, Atrazine	Region 5
Poso Slough

LOE ID:

69088

Pollutant:

Atrazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Atrazine.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for atrazine is 1 ug/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117398, Atrazine	Region 5
Poso Slough

LOE ID:

186417

Pollutant:

Atrazine

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 59 samples exceeded the water quality threshold for Atrazine.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for atrazine incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.001 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	159161	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159161, Cadmium	Region 5
Poso Slough

LOE ID:

186709

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for cadmium incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.005 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159161, Cadmium	Region 5
Poso Slough

LOE ID:

186711

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for cadmium incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.005 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159161, Cadmium	Region 5
Poso Slough

LOE ID:

330894

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 27 samples exceeded the water quality threshold for Cadmium.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for cadmium incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.005 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-03-02 and 2021-10-26

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 159161, Cadmium	Region 5
Poso Slough

LOE ID:

69095

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Cadmium.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for cadmium is 5 ug/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	117400	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117400, Carbofuran	Region 5
Poso Slough

LOE ID:

69098

Pollutant:

Carbofuran

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Carbofuran.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for Carbofuran is 18 ug/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117400, Carbofuran	Region 5
Poso Slough

LOE ID:

186979

Pollutant:

Carbofuran

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for Carbofuran incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.018 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	159162	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159162, Chlordane	Region 5
Poso Slough

LOE ID:

187143

Pollutant:

Chlordane

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Chlordane. Although a total of 54 samples were collected, 54 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Chlordane criterion for the protection of human health from the consumption of water and organisms is 0.00057 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159162, Chlordane	Region 5
Poso Slough

LOE ID:

333025

Pollutant:

Chlordane

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Total Chlordane. 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 Irrigated Lands Regulatory Program for the 2026 Integrated Report in Region 5

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The chlordane criterion for the protection of human health from the consumption of water and organisms is 0.00057 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-04-10 and 2019-08-13

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	159163	Region 5
Poso Slough

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)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159163, Copper	Region 5
Poso Slough

LOE ID:

331096

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 4 samples exceeded the water quality threshold for Copper.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-08-14 and 2021-10-26

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 159163, Copper	Region 5
Poso Slough

LOE ID:

346329

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	169919	Region 5
Poso Slough

Pollutant:	DDD (Dichlorodiphenyldichloroethane)
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:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 169919, DDD (Dichlorodiphenyldichloroethane)	Region 5
Poso Slough

LOE ID:

331223

Pollutant:

DDD (Dichlorodiphenyldichloroethane)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDD(p,p'). Although a total of 27 samples were collected, 27 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The 4,4'-DDD criterion for the protection of human health from the consumption of water and organisms is 0.00083 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-04-10 and 2021-03-19

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 169919, DDD (Dichlorodiphenyldichloroethane)	Region 5
Poso Slough

LOE ID:

188176

Pollutant:

DDD (Dichlorodiphenyldichloroethane)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDD(p,p'). Although a total of 54 samples were collected, 54 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDD(p,p) criteria for the protection of human health from the consumption of water and organisms is 0.00059 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	169924	Region 5
Poso Slough

Pollutant:	DDE (Dichlorodiphenyldichloroethylene)
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:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 169924, DDE (Dichlorodiphenyldichloroethylene)	Region 5
Poso Slough

LOE ID:

188199

Pollutant:

DDE (Dichlorodiphenyldichloroethylene)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and the results are as follows: 2 of the 2 samples exceeded the water quality threshold for DDE(p,p'). Although a total of 54 samples were collected, 52 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDE(p,p) criteria for the protection of human health from the consumption of water and organisms is 0.00059 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 169924, DDE (Dichlorodiphenyldichloroethylene)	Region 5
Poso Slough

LOE ID:

331259

Pollutant:

DDE (Dichlorodiphenyldichloroethylene)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDE(p,p'). Although a total of 27 samples were collected, 27 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The 4,4'-DDE [DDE(p,p')] criterion to protect human health from the consumption of water and organisms is 0.00059 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-04-10 and 2021-03-19

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	169929	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 169929, DDT (Dichlorodiphenyltrichloroethane)	Region 5
Poso Slough

LOE ID:

331273

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDT(p,p'). Although a total of 27 samples were collected, 27 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT(4,4') criterion for the protection of human health from the consumption of water and organisms is 0.00059 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-04-10 and 2021-03-19

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 169929, DDT (Dichlorodiphenyltrichloroethane)	Region 5
Poso Slough

LOE ID:

188260

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for DDT(p,p'). Although a total of 54 samples were collected, 54 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT(p,p) criteria for the protection of human health from the consumption of water and organisms is 0.00059 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117404	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117404, Dieldrin	Region 5
Poso Slough

LOE ID:

188838

Pollutant:

Dieldrin

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dieldrin. Although a total of 54 samples were collected, 54 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 117404, Dieldrin	Region 5
Poso Slough

LOE ID:

69114

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Dieldrin.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	117405	Region 5
Poso Slough

Pollutant:	Endosulfan sulfate
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:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

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 of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117405, Endosulfan sulfate	Region 5
Poso Slough

LOE ID:

189298

Pollutant:

Endosulfan sulfate

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 54 samples exceeded the water quality threshold for Endosulfan Sulfate.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan sulfate criteria for the protection of human health from the consumption of water and organisms is 110 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117406	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117406, Endrin	Region 5
Poso Slough

LOE ID:

69119

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Endrin.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117406, Endrin	Region 5
Poso Slough

LOE ID:

189582

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117407	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117407, Heptachlor	Region 5
Poso Slough

LOE ID:

69122

Pollutant:

Heptachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Heptachlor.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The CTR objective for Heptachlor to protect human health from the consumption of water and organisms is 0.00021 ug/L.

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117407, Heptachlor	Region 5
Poso Slough

LOE ID:

190532

Pollutant:

Heptachlor

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor. Although a total of 54 samples were collected, 54 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117408	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117408, Heptachlor epoxide	Region 5
Poso Slough

LOE ID:

69124

Pollutant:

Heptachlor epoxide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Heptachlor epoxide.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The CTR objective for Heptachlor epoxide to protect human health from the consumption of water and organisms is 0.0001 ug/L.

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117408, Heptachlor epoxide	Region 5
Poso Slough

LOE ID:

190437

Pollutant:

Heptachlor epoxide

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Heptachlor Epoxide. Although a total of 53 samples were collected, 53 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Heptachlor Epoxide criteria for the protection of human health from the consumption of water and organisms is 0.0001 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117424	Region 5
Poso Slough

Pollutant:	Hexachlorocyclohexane (HCH), alpha
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:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

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 of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117424, Hexachlorocyclohexane (HCH), alpha	Region 5
Poso Slough

LOE ID:

190037

Pollutant:

Hexachlorocyclohexane (HCH), alpha

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for HCH, alpha-. Although a total of 55 samples were collected, 55 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The alpha-HCH (alpha-BHC) criteria for the protection of human health from consumption of water and organisms is 0.0039 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117423	Region 5
Poso Slough

Pollutant:	Hexachlorocyclohexane (HCH), beta
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:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

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 of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117423, Hexachlorocyclohexane (HCH), beta	Region 5
Poso Slough

LOE ID:

190064

Pollutant:

Hexachlorocyclohexane (HCH), beta

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and the results are as follows: 0 of the 54 samples exceeded the water quality threshold for HCH, beta-. Although a total of 56 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The BHC, beta criteria for the protection of human health from the consumption of water and organisms is 0.014 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	159164	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159164, Lead	Region 5
Poso Slough

LOE ID:

190887

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: At a minimum, water designated for use as MUN shall not contain lead in excess of 0.015 mg/l.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159164, Lead	Region 5
Poso Slough

LOE ID:

190888

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Valley Region Sacramento River Basin and San Joaquin River Basin: At a minimum, water designated for use as MUN shall not contain lead in excess of 0.015 mg/l.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159164, Lead	Region 5
Poso Slough

LOE ID:

331728

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 28 samples exceeded the water quality threshold for Lead.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for lead incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.015 mg/L

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-03-02 and 2021-10-26

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	117410	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117410, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 5
Poso Slough

LOE ID:

69126

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for HCH, gamma.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for HCH, gamma (Lindane) is 0.2 ug/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117410, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 5
Poso Slough

LOE ID:

190051

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and the results are as follows: 0 of the 54 samples exceeded the water quality threshold for HCH, gamma-. Although a total of 56 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The BHC, gamma(Lindane) criteria for the protection of human health from the consumption of water and organisms is 0.019 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	165425	Region 5
Poso Slough

Pollutant:	Mercury
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:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

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 165425, Mercury	Region 5
Poso Slough

LOE ID:

331780

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Mercury.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The mercury criteria for the protection of human health from the consumption of water and organisms is 0.050 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2021-03-09 and 2021-03-19

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	117411	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117411, Methoxychlor	Region 5
Poso Slough

LOE ID:

191488

Pollutant:

Methoxychlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for Methoxychlor incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.03 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 117411, Methoxychlor	Region 5
Poso Slough

LOE ID:

69132

Pollutant:

Methoxychlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Methoxychlor.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for Methoxychlor, 30 ug/L, is incorporated by reference into the (Water Quality Control Plan, Central Valley Region, Sacramento and San Joaquin Basins).

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	159165	Region 5
Poso Slough

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)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159165, Nickel	Region 5
Poso Slough

LOE ID:

69139

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Nickel.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for nickel is 0.1 mg/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 159165, Nickel	Region 5
Poso Slough

LOE ID:

191823

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for nickel incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.1 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159165, Nickel	Region 5
Poso Slough

LOE ID:

331858

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for nickel incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.1 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-03-02 and 2021-10-26

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 159165, Nickel	Region 5
Poso Slough

LOE ID:

191864

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for nickel incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.1 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	159166	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159166, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 5
Poso Slough

LOE ID:

331887

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Primary California Maximum Contaminant Level for nitrate + nitrite (as N) incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 10 mg/L (California Code of Regulations, Title 22).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-03-02 and 2021-10-26

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 159166, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 5
Poso Slough

LOE ID:

192163

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 79 samples exceeded the water quality threshold for Nitrate + Nitrite as N.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Maximum Contaminant Level for nitrate + nitrite (as N) incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 10 mg/L (California Code of Regulations, Title 22).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-09-16 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159166, Nitrate/Nitrite (Nitrite + Nitrate as N)	Region 5
Poso Slough

LOE ID:

69140

Pollutant:

Nitrate/Nitrite (Nitrite + Nitrate as N)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 17 samples exceed the criterion for Nitrate/Nitrite as N.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for nitrate + nitrite (as N) is 10.0 mg/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 4/8/2008-8/11/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	117414	Region 5
Poso Slough

Pollutant:	Oxamyl (Vydate)
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:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

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 of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117414, Oxamyl (Vydate)	Region 5
Poso Slough

LOE ID:

192580

Pollutant:

Oxamyl (Vydate)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for Oxamyl incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.05 mg/L

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	159168	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159168, Selenium	Region 5
Poso Slough

LOE ID:

69160

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Selenium.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for selenium is 0.05 mg/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 159168, Selenium	Region 5
Poso Slough

LOE ID:

193528

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for selenium incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.05 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 159168, Selenium	Region 5
Poso Slough

LOE ID:

332633

Pollutant:

Selenium

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 44 samples exceeded the water quality threshold for Selenium.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for selenium incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.05 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-03-02 and 2022-02-08

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	159169	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159169, Simazine	Region 5
Poso Slough

LOE ID:

332678

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for Simazine incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.004 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-08-14 and 2021-03-19

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 159169, Simazine	Region 5
Poso Slough

LOE ID:

69166

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Simazine.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for Simazine is 4 ug/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 159169, Simazine	Region 5
Poso Slough

LOE ID:

193580

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Primary Maximum Contaminant Level for Simazine incorporated by reference in the Water Quality Control Plan for the Sacramento and San Joaquin River Basins is 0.004 mg/L.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	169145	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

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 169145, Specific Conductivity	Region 5
Poso Slough

LOE ID:

346624

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 6 of the 8 samples fall within the range, and 2 of 8 samples fall below the threshold.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference into the Water Quality Control Plan for the Sacramento and San Joaquin River Basins specifies a range for specific conductance of 900-1600 uS/cm assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2017-08-08

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition

Line of Evidence (LOE) for Decision ID 169145, Specific Conductivity	Region 5
Poso Slough

LOE ID:

332815

Pollutant:

Specific Conductivity

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 6 samples exceeded the upper limit of the range for SpecificConductivity. Additionally, 3 of the 6 samples fall within the range, and 3 of 6 samples fall below the threshold.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2017-10-10 and 2022-02-08

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program


DECISION ID	166379	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 166379, Total Dissolved Solids	Region 5
Poso Slough

LOE ID:

346737

Pollutant:

Total Dissolved Solids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the upper limit of the range for Total Dissolved Solids. Additionally, 7 of the 9 samples fall within the range, and 2 of 9 samples fall below the threshold.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California Secondary MCL that is incorporated by reference into the Water Quality Control Plan for the Sacramento and San Joaquin River Basins specifies a range for total dissolved solids of 500-1000 mg/L assessed as an annual average.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117419	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117419, Toxaphene	Region 5
Poso Slough

LOE ID:

69167

Pollutant:

Toxaphene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for Toxaphene.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Toxaphene criterion for the protection of human health from the consumption of water and organisms is 0.00073 ug/L. (California Toxics Rule, 2000)

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 117419, Toxaphene	Region 5
Poso Slough

LOE ID:

193902

Pollutant:

Toxaphene

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Toxaphene. Although a total of 55 samples were collected, 55 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Toxaphene criteria for the protection of human health from the consumption of water and organisms is 0.00073 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (541XPSAIA).

Temporal Representation:

Date for this waterbody was collected over the date range 2010-12-21 to 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	159170	Region 5
Poso Slough

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)(2020)
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	LOE 194381 has been replaced by LOE 346782 due to a reassessment of data. LOEs for this waterbody-pollutant combination from previous cycles were reviewed, determined to be inaccurate, and removed. Readily available data for this waterbody were not used to determine standards attainment as the status of the waterbody as a water of the United States is uncertain. The 303(d) list is authorized under the Clean Water Act and is therefore limited to waters of the United States. Data will be used to determine standards attainment during a future Integrated Report cycle if it is determined that this water body is classified as a water of the United States.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the listing status for this water body-pollutant combination should not change this cycle because of a lack of clarity in the status of this water body under the Clean Water Act.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 159170, Zinc	Region 5
Poso Slough

LOE ID:

333077

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2018-08-14 and 2021-10-26

Environmental Conditions:

QAPP Information:

QAPP Reference for Irrigated Lands Regulatory Program

QAPP Information Reference(s):

QAPP Reference for Irrigated Lands Regulatory Program

Line of Evidence (LOE) for Decision ID 159170, Zinc	Region 5
Poso Slough

LOE ID:

346782

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 541XPSAIA (Poso Slough at Indiana Ave).

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117403	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

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 of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117403, alpha-Endosulfan (Endosulfan 1)	Region 5
Poso Slough

LOE ID:

189438

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The alpha-endosulfan criteria for the protection of human health from the consumption of water and organisms is 110 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	117415	Region 5
Poso Slough

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

Regional Board Conclusion:	Readily available data for this water body have not been used to determine standards attainment. No decision has been made regarding beneficial use support due to a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule. A decision regarding the beneficial use support of this water body will be made during a future Integrated Report cycle if it is determined that this water body is classified as a Water of the United States under the Navigable Waters Protection Rule.

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 of a lack of clarity in the status of this water body under the Clean Water Act and the Navigable Waters Protection Rule.

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 117415, beta-Endosulfan (Endosulfan 2)	Region 5
Poso Slough

LOE ID:

189391

Pollutant:

beta-Endosulfan (Endosulfan 2)

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:

Water Board staff assessed Westside San Joaquin River Watershed Coalition data for Poso Slough to determine beneficial use support and results are as follows: 0 of 55 samples exceeded the water quality threshold for Endosulfan II.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The beta-endosulfan criteria for the protection of human health from the consumption of water and organisms is 110 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

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

Temporal Representation:

The samples were collected between the dates of 2010-12-21 and 2018-02-13

Environmental Conditions:

QAPP Information:

Pacific EcoRisk. 2013. QAPP for Westside San Joaquin River Watershed Coalition.

QAPP Information Reference(s):

QAPP for Westside San Joaquin River Watershed Coalition


DECISION ID	89315	Region 5
Poso Slough

Pollutant:	Methyl Parathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Data for this water segment-pollutant combination were received by the State Water Resources Control Board as part of the data solicitation for the 2014 Integrated Report Cycle. These data were not assessed as part of the 2014 Integrated Report.

Regional Board Decision Recommendation:	Data for this water segment - pollutant combination were not assessed by RWQCB staff during the 2014 Integrated Report cycle. RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list at this time. These data will be assessed by RWQCB staff during a future Integrated Report cycle to determine the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 89315, Methyl Parathion	Region 5
Poso Slough

LOE ID:

69138

Pollutant:

Methyl Parathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Parathion, Methyl.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The NAS health advisory level for methyl parathion is 30 µg/L.

Guideline Reference:

National Academy of Sciences - Volume I Drinking Water and Health

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	89391	Region 5
Poso Slough

Pollutant:	Nitrogen, Nitrate
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:	Data for this water segment-pollutant combination were received by the State Water Resources Control Board as part of the data solicitation for the 2014 Integrated Report Cycle. These data were not assessed as part of the 2014 Integrated Report.

Regional Board Decision Recommendation:	Data for this water segment - pollutant combination were not assessed by RWQCB staff during the 2014 Integrated Report cycle. RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list at this time. These data will be assessed by RWQCB staff during a future Integrated Report cycle to determine the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 89391, Nitrogen, Nitrate	Region 5
Poso Slough

LOE ID:

69141

Pollutant:

Nitrogen, Nitrate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Nitrate as N.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for nitrate (NO3 as N) is 10.0 mg/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected on a single day 3/18/2008.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	89392	Region 5
Poso Slough

Pollutant:	Nitrogen, Nitrite
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:	Data for this water segment-pollutant combination were received by the State Water Resources Control Board as part of the data solicitation for the 2014 Integrated Report Cycle. These data were not assessed as part of the 2014 Integrated Report.

Regional Board Decision Recommendation:	Data for this water segment - pollutant combination were not assessed by RWQCB staff during the 2014 Integrated Report cycle. RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list at this time. These data will be assessed by RWQCB staff during a future Integrated Report cycle to determine the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 89392, Nitrogen, Nitrite	Region 5
Poso Slough

LOE ID:

69142

Pollutant:

Nitrogen, Nitrite

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceed the criterion for Nitrite as N.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The California primary maximum contaminant level for nitrite (as N) is 1 mg/L.

Objective/Criterion Reference:

Maximum Contaminant Levels for organic and inorganic chemicals. CCR Title 22

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected on a single day 3/18/2008.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	89393	Region 5
Poso Slough

Pollutant:	Parathion
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Data for this water segment-pollutant combination were received by the State Water Resources Control Board as part of the data solicitation for the 2014 Integrated Report Cycle. These data were not assessed as part of the 2014 Integrated Report.

Regional Board Decision Recommendation:	Data for this water segment - pollutant combination were not assessed by RWQCB staff during the 2014 Integrated Report cycle. RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list at this time. These data will be assessed by RWQCB staff during a future Integrated Report cycle to determine the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 89393, Parathion	Region 5
Poso Slough

LOE ID:

69149

Pollutant:

Parathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for Parathion, Ethyl.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

The NAS health advisory level for parathion or ethyl parathion is 30 µg/L.

Guideline Reference:

National Academy of Sciences - Volume I Drinking Water and Health

Spatial Representation:

Data for this line of evidence for Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	89479	Region 5
Poso Slough

Pollutant:	alpha.-BHC (Benzenehexachloride or alpha-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Data for this water segment-pollutant combination were received by the State Water Resources Control Board as part of the data solicitation for the 2014 Integrated Report Cycle. These data were not assessed as part of the 2014 Integrated Report.

Regional Board Decision Recommendation:	Data for this water segment - pollutant combination were not assessed by RWQCB staff during the 2014 Integrated Report cycle. RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list at this time. These data will be assessed by RWQCB staff during a future Integrated Report cycle to determine the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 89479, alpha.-BHC (Benzenehexachloride or alpha-HCH)	Region 5
Poso Slough

LOE ID:

69085

Pollutant:

alpha.-BHC (Benzenehexachloride or alpha-HCH)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 0 samples exceed the criterion for HCH, alpha.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The HCH, alpha criterion, 0.0039 ug/L, is for the protection of human health from the consumption of water and organisms. (California Toxics Rule, 2002)

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	89478	Region 5
Poso Slough

Pollutant:	beta-BHC (Benzenehexachloride or beta-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	Data for this water segment-pollutant combination were received by the State Water Resources Control Board as part of the data solicitation for the 2014 Integrated Report Cycle. These data were not assessed as part of the 2014 Integrated Report.

Regional Board Decision Recommendation:	Data for this water segment - pollutant combination were not assessed by RWQCB staff during the 2014 Integrated Report cycle. RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list at this time. These data will be assessed by RWQCB staff during a future Integrated Report cycle to determine the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 89478, beta-BHC (Benzenehexachloride or beta-HCH)	Region 5
Poso Slough

LOE ID:

69094

Pollutant:

beta-BHC (Benzenehexachloride or beta-HCH)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Municipal & Domestic Supply

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Ag Waiver data for Poso Slough to determine beneficial use support and results are as follows: 0 of 7 samples exceed the criterion for HCH, beta.

Data Reference:

Data for Various Pollutants in Westside San Joaquin Water Quality Coalition, 2004-2009.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The HCH, beta criterion for the protection of human health from the consumption of water and organisms is 0.014 ug/L (California Toxics Rule, 2002).

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 Poso Slough was collected at 1 monitoring site [Poso Slough at Indiana Ave - 541XPSAIA]

Temporal Representation:

Data was collected over the time period 3/18/2008-2/12/2009.

Environmental Conditions:

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

QAPP Information:

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

QAPP Information Reference(s):