# Draft 2008 California 303(d)/305(b) Integrated Report

# Supporting Information

## Regional Board 5 - Central Valley Region

Water Body Name: | Elder Creek (at Gerber)
Water Body ID: | CAR5042007020000216112211
Water Body Type: | River & Stream

DECISION ID | 12993
Pollutant: | Chlorpyrifos
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | 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. Ten samples exceed the narative 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. Ten of twenty-nine available 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. Eight of thirty-three available 1-hour average chlorpyrifos concentrations exceeded the 1-day 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.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 12993

LOE ID: | 22093
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 21
Number of Exceedances: | 10
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Twenty-five water samples were collected from Elder Creek from February 2001 to April 2003, representing twenty-one calculated 4-day average chlorpyrifos concentrations and twenty-five 1-hour average chlorpyrifos concentrations. Ten of the twenty-one available calculated 4-day average chlorpyrifos concentrations exceeded the 4-day average chlorpyrifos criterion of 0.015 ug/L. Eight of the twenty-five available 1-hour average chlorpyrifos concentrations exceeded the 1-hour average chlorpyrifos criterion of 0.025 ug/L.
Data Reference: | Concentrations of pesticides in Sacramento metropolitan area rainwater and creeks during the 2001, 2002, 2003 orchard dormant spray season. Rancho Cordova, CA: Central Valley RWQCB
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Water quality 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
| Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | California Department of Fish and Game Hazard Assessment Chlorpyrifos Criteria: 0.015 ug/L as a4-day average chlorpyrifos concentration, and 0.025 ug/L as a 1-hour average chlorpyrifos 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 Elder Creek at five sites: Excelsior Road, Bradshaw Road, Elder Creek Road, Elk Grove-Florin Road, and Franklin Blvd.
Temporal Representation: | Samples were collected from February 2001 to April 2003 at variable intervals (e.g. every three to five days) during storms.
Environmental Conditions: |
QAPP Information: | Spector et al., 2004. Concentrations of Pesticides in Sacramento Metropolitan Area Rainwater and Creeks during the 2001, 2002 and 2003 Orchard Dormant Spray Seasons.
QAPP Information Reference(s):
LOE ID: | 22094
Pollutant: | Chlorpyrifos
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Thirteen water samples were collected from Elder Creek in February 2004 to April 2007, representing eight calculated 4-day average chlorpyrifos concentrations and eight 1-hour average chlorpyrifos concentrations. Zero of the eight available calculated 4-day average chlorpyrifos concentrations exceeded the 4-day average chlorpyrifos criterion of 0.015 ug/L. Zero of the eight available 1-hour average chlorpyrifos concentrations exceeded the 1-hour average chlorpyrifos criterion of 0.025 ug/L. Five samples had a detection limit of 0.05 ug/L, which is higher than both the water quality criteria guideline values of 0.015 and 0.025 ug/L. Therefore, in accordance with Section 6.1.5.5 of the Listing Policy, these five samples were not used in this analysis.
Data Reference: | Sacramento River watershed program (SRWP) water quality database. Davis, CA
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Water quality 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
| Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | California Department of Fish and Game Hazard Assessment Chlorpyrifos Criteria: 0.015 ug/L as a 4-day average chlorpyrifos concentration, and 0.025 ug/L as a 1-hour average chlorpyrifos concentration, not to be exceeded more 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 Elder Creek at Morrison Creek.
Temporal Representation: | Samples were collected at variable intervals (e.g., every two weeks or every twenty days) from February 2004 to April 2007.
Environmental Conditions: |
QAPP Information: | Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2002-0206) requirements (CVRWQCB, 2002)
QAPP Information Reference(s):

DECISION ID | 12992
Pollutant: | Diazinon
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | New Decision
Revision Status | Revised
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Weight of Evidence: | 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 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. Four of twelve available calculated 4-day average diazinon concentrations exceeded the 4-day average diazinon criterion, and this exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Three of twelve available 1-hour average diazinon concentrations exceeded the 4-day average diazinon 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.
RWQCB Board Decision / Staff Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
SWRCB Board Decision / Staff Recommendation: |
USEPA Decision: |

Lines of Evidence (LOEs) for Decision ID 12992

LOE ID: | 22095
Pollutant: | Diazinon
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Warm Freshwater Habitat
Aquatic Life Use: | Warm Freshwater Habitat
Number of Samples: | 12
Number of Exceedances: | 4
Data and Information Type: | PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: | Twelve water samples were collected from Elder Creek from February 2002 through February 2007, representing twelve calculated 4-day average diazinon concentrations and twelve 1-hour average diazinon concentrations. Four of the twelve available calculated 4-day average diazinon concentrations exceeded the 4-day average diazinon criterion of 0.100 ug/L. Three of the twelve available 1-hour average diazinon concentrations exceeded the 1-hour average diazinon criterion of 0.160 ug/L.
Data Reference: | Sacramento River watershed program (SRWP) water quality database. Davis, CA
Water Quality Objective/Criterion: | No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses. All waters shall be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, plant, animal, or aquatic life.
Objective/Criterion Reference: | Water quality 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
| Central Valley Regional Water Quality Control Board. Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board - Central Valley Region
Evaluation Guideline: | California Department of Fish and Game Hazard Assessment Diazinon Criteria: 0.160 ug/L as a 1-hour average concentration, and 0.100 ug/L as a 4-day 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 Elder Creek at Morrison Creek.
Temporal Representation: | Samples were collected on 02/02/2004, 02/18/2004, 04/13/2004, 10/06/2004, 01/28/2005, 02/15/2005, 04/12/2005, 02/07/2006, 02/27/2006, 03/06/2006, 12/08/2006, and 02/09/2007.
Environmental Conditions: | Elder Creek is located in the Sacramento urban area.
QAPP Information: | Data quality: Good. Monitoring was conducted in accordance with Central Valley Water Board Monitoring and Reporting Program (order number R5-2002-0206) requirements (CVRWQCB, 2002)
QAPP Information Reference(s):