Final California 2012 Integrated Report( 303(d) List/305(b) Report)

Supporting Information

Regional Board 5 - Central Valley Region

Water Body Name:	Westley Wasteway (Stanislaus County)
Water Body ID:	CAR5411000020080808192151
Water Body Type:	River & Stream


DECISION ID	23830	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Oxygen, Dissolved
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of 26 samples fell below the minimum criterion water quality objective listed in the Sacramento/San Joaquin River Basin Plan and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23830, Oxygen, Dissolved	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

25191

Pollutant:

Oxygen, Dissolved

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Twenty-six samples were taken from the Westley Wasteway between 2004 and 2006. None of the twenty-six samples fell below the Water Quality Objective for minimum dissolved oxygen content in surface water.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

From the Sacramento/San Joaquin River Basin Plan the (WARM) Warm Freshwater Habitat criterion is a Minimum Dissolved Oxygen content of 5mg/L.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from the Westley Wasteway at Refuge Ponds and near Cox Road in Stanislaus County.

Temporal Representation:

Samples were collected between July 2004 and October 2006. Samples were collected at monthly intervals.

Environmental Conditions:

QAPP Information:

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):


DECISION ID	23631	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Salinity
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)(2010)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Four of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Four of 46 samples exceeded the water quality objectives for electrical conductivity and total dissolved solids (collectively salinity) and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23631, Salinity	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23249

Pollutant:

Salinity

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:

Twenty-four samples were taken from Westley Wasteway between 2004 and 2006. None of the twenty-four samples exceed the California Secondary MCL for Municipal Water Quality Objectives for electrical conductivity in surface water.

Data Reference:

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

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The water quality objective used was the California Secondary MCL recommended level of 900 uS/cm. The Basin Plan includes chemical constituent water quality objectives that include (by reference) secondary maximum contaminant levels (MCL's) protective of MUN (CVRWQCB, 2007a).The secondary MCL's for electrical conductivity provide a range of values including a recommended level (900 uS/cm), upper level (1600 uS/cm) and a short-term level (2200 uS/cm). The 'recommended' concentration was used as it is intended to be protective of all drinking water uses. Though individual listing evaluations did not look at the water supply source serving the given geographic area, there are certain areas that receive supply waters (such as the Delta Mendota Canal) that at times may be elevated above the recommended level of the secondary MCL. Where future information is made available to document this to be the case, these water bodies may be re-evaluated in future listing cycles.

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

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from Westley Wasteway at Refuge Ponds and near Cox Road in Stanislaus County.

Temporal Representation:

Samples were collected between July 2004 and October 2006. Samples were collected at monthly intervals.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 23631, Salinity	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23250

Pollutant:

Salinity

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:

Twenty-two samples were taken from Westley Wasteway between 2004 and 2006. Four of the twenty-four samples exceed the California Secondary MCL for Municipal Water Quality Objectives for total dissolved solids in surface water.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The water quality objective used was the California Secondary MCL recommended level of 500 mg/L. The Basin Plan includes chemical constituent water quality objectives that include (by reference) secondary maximum contaminant levels (MCL's) protective of MUN (CVRWQCB, 2007a).The secondary MCL's for TDS provide a range of values including a recommended level (500 mg/L), upper level (1000 mg/L) and a short-term level (1500 mg/L). The 'recommended' concentration was used as it is intended to be protective of all drinking water uses. Though individual listing evaluations did not look at the water supply source serving the given geographic area, there are certain areas that receive supply waters (such as the Delta Mendota Canal) that at times may be elevated above the recommended level of the secondary MCL. Where future information is made available to document this to be the case, these water bodies may be re-evaluated in future listing cycles.

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

California Code of Regulations, Title 22, Division 4, Chapter 15. Domestic Water Quality and Monitoring

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from Westley Wasteway at Refuge Ponds and near Cox Road in Stanislaus County.

Temporal Representation:

Samples were collected between July 2004 and October 2006. Samples were collected at monthly intervals.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	23630	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Trifluralin
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. One of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 20 samples exceeded the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23630, Trifluralin	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23251

Pollutant:

Trifluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

2 water samples were collected from Westley Wasteway near Cox Road in June 2001 and August 2001 representing 2 concentrations.0 of 2 concentrations exceeded the maximum concentration of 0.70 ug/L.

Data Reference:

Correspondence between the Department of Pesticide Regulation and Central Valley Regional Water Quality Control Board regarding water quality data for waterbodies in the Central Valley

Report and data files for pesticides in the Sacramento River, Winter 2005

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 (CVRWQCB, 2007).All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life (CVRWQCB, 2007).

Objective/Criterion Reference:

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 Board will use the best available technical information to evaluate compliance with the narrative objectives. Other available technical information on the pesticide (such as Lowest Observed Effect Concentrations and No Observed Effect Levels), the water bodies and organisms involved will be evaluated to determine if lower concentrations are required to meet the narrative objectives. (CRWQCB, 2006).Lowest Observed Effects Concentration for Pimephales promelas is 0.7 ug/L Ecotoxicity Study 1582-09-8 (USEPA, 2008)

Guideline Reference:

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

Spatial Representation:

Samples were collected from Westley Wasteway near Cox Road

Temporal Representation:

Samples were collected in June 2001 and August 2001.

Environmental Conditions:

QAPP Information:

Data quality: Good. Minimum requirements for the CDPR Surface Water Database are: Name of the sampling agency or organization, Date that each sample was collected, Date of each sample analysis, County where samples were taken, Detailed sampling location information (including latitude and longitude or township/range/section if available), detailed map or description of each sampling site (i.e., address, cross roads, etc.), Name or description of water body sampled, Name of the active ingredient analyzed for; concentration detected (with unit of measurement), and limit of quantitation, Description of analytical QA/QC plan, or statement that no formal plan exists. Additional optional requirements are included on DPR's webpage at http://www.cdpr.ca.gov/docs/emon/surfwtr/caps/req.htm

QAPP Information Reference(s):

Standard Operating Procedure for Conducting Surface Water Monitoring for Pesticides

Line of Evidence (LOE) for Decision ID 23630, Trifluralin	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23253

Pollutant:

Trifluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

11 water samples were collected from Westley Wasteway near Cox Road from July 2004 through June 2006 representing 11 concentrations.1 of 11 concentrations exceeded the maximum concentration of 0.70 ug/L.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

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

Spatial Representation:

Samples were collected from Westley Wasteway near Cox Road.

Temporal Representation:

Samples were collected at variable intervals (biweekly, weekly, monthly) from July 2004 through June 2006.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 23630, Trifluralin	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23252

Pollutant:

Trifluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

7 water samples were collected from Westley Wasteway near Cox Road from June 1994 through July 1994, and in June 2001 and August 2001 representing 7 concentrations.0 of 7 concentrations exceeded the maximum concentration of 0.70 ug/L.

Data Reference:

National Water Quality Assessment database, San Joaquin and Tulare Basins data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

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

Spatial Representation:

Samples were collected from Westley Wasteway near Cox Road.

Temporal Representation:

Samples were collected at variable intervals (biweekly, weekly, monthly) from June 1994 through July 1994, and in June 2001 and August 2001.

Environmental Conditions:

QAPP Information:

Data quality: Good. In accordance with section 6.1.4 of the Listing Policy, data from major monitoring programs in California and Published USGS reports are considered of adequate quality.

QAPP Information Reference(s):


DECISION ID	23685	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Unknown Toxicity
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)(2010)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. None of 12 samples exceeded the water quality objective for ceriodaphnia and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. In addition, none of 12 samples exceeded the water quality objective for fathead minnow and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. Lastly, none of 12 samples exceeded the water quality objective for selenastrum and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23685, Unknown Toxicity	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23240

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Zero of the 12 samples tested with Ceriodaphnia dubia were toxic and violated the narrative toxicity objective.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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

Evaluation Guideline:

Statistically significant difference from control using a t-test with 4-day acute-style toxicity tests.

Guideline Reference:

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

Spatial Representation:

Samples were collected from two locations: Westley Wasteway at Refuge Ponds and Westley Wasteway near Cox Road.

Temporal Representation:

Samples were collected from July 2004 to August 2006.

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 23685, Unknown Toxicity	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23246

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Zero of the 12 samples tested with Pimephales promelas were toxic and violated the narrative toxicity objective.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Statistically significant difference from control using a t-test with 4-day acute-style toxicity tests.

Guideline Reference:

Spatial Representation:

Samples were collected from two locations: Westley Wasteway at Refuge Ponds and Westley Wasteway near Cox Road.

Temporal Representation:

Samples were collected from July 2004 to August 2006.

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 23685, Unknown Toxicity	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23248

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

Zero of 12 samples tested with Selenastrum capricornutum were toxic and violated the narrative toxicity objective.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Statistically significant difference from control using a t-test with 4-day chronic-style toxicity tests.

Guideline Reference:

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

Spatial Representation:

Samples were collected from two locations: Westley Wasteway at Refuge Ponds and Westley Wasteway near Cox Road.

Temporal Representation:

Samples were collected from July 2004 to August 2006.

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):


DECISION ID	23632	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	pH
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Four of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Four of 34 samples exceeded the pH objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23632, pH	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23247

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

The Westside San Joaquin Water Quality Coalition collected 34 samples from July 2004 to October 2006. Four out of 34 samples were outside the acceptable range; two samples were higher than the acceptable range and two samples were lower than the acceptable range.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH of water shall not be depressed below 6.5,raised above 8.5, or changed at any time more than 0.5 units from normal ambient pH.

Objective/Criterion Reference:

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

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from two locations: Westley Wasteway at Refuge Ponds and Westley Wasteway near Cox Road.

Temporal Representation:

Sampling occurred from July 2004 to October 2006.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	23617	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Chlorpyrifos
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2010)
Revision Status	Original
Sources:	Source Unknown
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Two samples exceed the narrative toxicity water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of four calculated 4-day average chlorpyrifos concentrations exceeded the 4-day average chlorpyrifos criterion, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Two of four 1-hour average chlorpyrifos concentrations exceeded the 1-hour average chlorpyrifos criterion, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 5. 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:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23617, Chlorpyrifos	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23241

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Eleven water samples were collected from Westley Wasteway from July 2004 through August 2006, representing four calculated 4-day average chlorpyrifos concentrations and four 1-hour average chlorpyrifos concentrations. Two of four calculated 4-day average chlorpyrifos concentrations exceeded the 4-day average chlorpyrifos criterion of 0.015 ug/L. Two of four 1-hour average chlorpyrifos concentrations exceeded the 1-hour average chlorpyrifos criterion of 0.025 ug/L. Seven water samples had method detection limits (0.02, 0.05, 0.032 ug/L) higher than the CDFG Hazard Assessment Chlorpyrifos 1-hour Criterion (0.015 ug/L) and, in accordance with Section 6.1.5.5 of the Listing Policy, these samples were not included in this analysis.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

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

Evaluation Guideline:

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

Guideline Reference:

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

Spatial Representation:

Samples were collected from Westley Wasteway near Cox Road.

Temporal Representation:

Samples were collected biweekly from June 2004 through August 2006.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	26702	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Dimethoate
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2010)
Revision Status	Original
Sources:	Source Unknown
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Four of the samples exceed the narrative toxicity water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Five of 12 samples exceed the Evaluation Guideline of 0.2 ug/L, which exceed the narrative toxicity objective, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 26702, Dimethoate	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

26127

Pollutant:

Dimethoate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Twelve water samples were collected from Westley Wasteway, under the Irrigated Lands Regulatory Program, between July 2004 and August 2006. Five of the 12 water samples contained dimethoate at concentrations that exceeded the Evaluation Guideline value of 0.2 ug/L.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life. Where valid testing has developed 96 hour LC50 values for aquatic organisms (the concentration that kills one half of the test organisms in 96 hours), the Board will consider one tenth of this value for the most sensitive species tested as the upper limit (daily maximum) for the protection of aquatic life. Other available technical information on the pesticide (such as Lowest Observed Effect Concentrations and No Observed Effect Levels), the water bodies and the organisms involved will be evaluated to determine if lower concentrations are required to meet the narrative objectives (CVRWQCB, 2007).

Objective/Criterion Reference:

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

Evaluation Guideline:

The one-tenth of 96-hour LC50 value, tested with dimethoate on the most sensitive species in freshwater (Cyclops strenuus, a copepod crustacean), is 0.2 ug/L.

Guideline Reference:

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

Spatial Representation:

Water samples were collected from Westley Westeway near Cox Road and at Refuge Ponds.

Temporal Representation:

Samples were collected from Westley Wasteway on 6 July 2004, 10 August 2004, 8 March 2005, 12 April 2005, 10 May 2005, 14 June 2005, 12 July 2005, 9 August 2005 (two samples), 9 May 2005, 13 June 2006, and 8 August 2008.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	23831	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Escherichia coli (E. coli)
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2010)
Revision Status	Original
Sources:	Source Unknown
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Thirteen of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Thirteen of 22 samples exceeded the the E. Coli objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23831, Escherichia coli (E. coli)	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23243

Pollutant:

Escherichia coli (E. coli)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

The Westside San Joaquin River Water Quality Coalition collected 22 samples from July 2004 to October 2006. Thirteen out of 22 samples exceeded the evaluation objective.

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

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

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

Evaluation Guideline:

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

Guideline Reference:

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

Spatial Representation:

Samples were collected at two locations: Westley Wasteway at Refuge Ponds and Westley Wasteway near Cox Road.

Temporal Representation:

Sampling occurred from July 2004 to October 2006.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):


DECISION ID	23684	Region 5
Westley Wasteway (Stanislaus County)

Pollutant:	Sediment Toxicity
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	List on 303(d) list (TMDL required list)(2010)
Revision Status	Original
Sources:	Source Unknown
Expected TMDL Completion Date:	2021
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Two of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of 3 samples exceeded the narrative toxicity objective and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Staff Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	The decision has not changed. Region 5 data was not included in the 2012 Integrated Report so all decisions are carried over from the 2010 listing cycle. 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 23684, Sediment Toxicity	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23245

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

The one sample tested with Hyalella azteca was toxic and violated the narrative toxicity objective. One sample collected at WWNCR exhibited a statistically significant decrease in survival compared to the control. The sample date and percent of control (in parentheses) are as follows:10 October 2005 (0)

Data Reference:

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

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

Statistically significant difference from control using a t-test with 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 Westley Wasteway near Cox Road.

Temporal Representation:

The sample was collected October 10, 2005.

Environmental Conditions:

QAPP Information:

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

QAPP Information Reference(s):

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

Line of Evidence (LOE) for Decision ID 23684, Sediment Toxicity	Region 5
Westley Wasteway (Stanislaus County)

LOE ID:

23244

Pollutant:

Toxicity

LOE Subgroup:

Toxicity

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

TOXICITY TESTING

Data Used to Assess Water Quality:

One of the 2 samples tested with Hyalella azteca was toxic and violated the narrative toxicity objective. One sample collected at Westley Wasteway near Cox Road exhibited a statistically significant decrease in survival compared to the control. The sample date and percent of control (in parentheses) are as follows:11 September 2006 (1)

Data Reference:

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

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

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

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

Samples were collected from Westley Wasteway near Cox Road.

Temporal Representation:

Samples were collected in September 2004 and September 2006

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):