Final California 2024 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name:	Dry Canyon Creek (Ventura County)
Water Body ID:	CAR4082700020210322036804
Water Body Type:	River & Stream


DECISION ID	140694	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 0 of 25 samples exceeded the 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140694, Aldrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

256407

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Aldrin.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The aldrin criterion maximum concentration (expressed as a 1-day average) to protect aquatic life in freshwater is 1.5 ug/L. The criterion of 3 ug/L provided in the California Toxics Rule is an instantaneous maximum concentration and was divided by 2 in order to better represent a criterion maximum concentration (CMC) value as specified in footnote (g) of Table (b)(1) of the 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: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140694, Aldrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

256416

Pollutant:

Aldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for Aldrin.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

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: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140675	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 140675, Atrazine	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

257364

Pollutant:

Atrazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Atrazine.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: Surface waters shall not contain concentrations of chemical constituents in amounts that adversely affect any designated beneficial use.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of < 1 ug/L for a nonvascular plant (acute). The benchmark was derived from a 'less-than' value (for example, <1,500) and may underestimate toxicity.

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2010-12-19

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140676	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 140676, Chlordane	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

267346

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) 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 25 samples were collected, 25 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:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The chlordane criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0043 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140676, Chlordane	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

267512

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) 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 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The chlordane criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0043 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140677	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 1 of 2 and 0 of 25 samples exceeded the criterion and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140677, Chlorpyrifos	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

258462

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 1 of 2 samples exceeded the water quality threshold for Chlorpyrifos.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The freshwater criterion continuous concentration to protect aquatic organisms is 0.015 ug/L (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005).

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

Guideline Reference:

Water quality criteria for diazinon and chlorpyrifos. Administrative Report 00-3. Rancho Cordova, CA: Pesticide Investigations Unit, Office of Spills and Response. CA Department of Fish and Game (with minor corrections to significant figures as described in Beaulaurier et al., 2005).

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140677, Chlorpyrifos	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

258254

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for Chlorpyrifos.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

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

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140696	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 140696, Deltamethrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

259754

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Deltamethrin. Although a total of 24 samples were collected, 23 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140696, Deltamethrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260290

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Deltamethrin. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for deltamethrin is the USEPA Aquatic Life Benchmark of 0.000026 ug/L for an invertebrate (chronic).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140679	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 1 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140679, Diazinon	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260164

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 1 of 25 samples exceeded the water quality threshold for Diazinon.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.10 ug/L (4 day average)(Finlayson, 2004).

Guideline Reference:

Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140679, Diazinon	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260204

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.10 ug/L (4 day average)(Finlayson, 2004).

Guideline Reference:

Water quality for diazinon. Memorandum to J. Karkoski, Central Valley RWQCB. Rancho Cordova, CA: Pesticide Investigation Unit, CA Department of Fish and Game

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140680	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 0 of 25 samples exceeded the criterion and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140680, Dieldrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260551

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140680, Dieldrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260488

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for Dieldrin.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The dieldrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140681	Region 4
Dry Canyon Creek (Ventura County)

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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 0 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140681, Endosulfan sulfate	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260823

Pollutant:

Endosulfan sulfate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA National Recommended Water Quality Criteria toxicity threshold for endosulfan sulfate for freshwater aquatic life protection is 0.056 ug/l (24 hour average)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140681, Endosulfan sulfate	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260773

Pollutant:

Endosulfan sulfate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for Endosulfan Sulfate.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The USEPA National Recommended Water Quality Criteria toxicity threshold for endosulfan sulfate for freshwater aquatic life protection is 0.056 ug/l (24 hour average)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140682	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 0 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140682, Endrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

261245

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for Endrin.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140682, Endrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

261242

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endrin criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.036 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140683	Region 4
Dry Canyon Creek (Ventura County)

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:	New Decision
Revision Status	Revised
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 0 of 24 samples exceeded the criteria and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140683, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

261929

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for HCH, gamma-.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The gamma-BHC (Lindane, gamma-HCH) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L. (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140683, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

261990

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The gamma-BHC (Lindane, gamma-HCH) criterion maximum concentration to protect aquatic life in freshwater is 0.95 ug/L. (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140684	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 2 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140684, Malathion	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

262826

Pollutant:

Malathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 2 of 25 samples exceeded the water quality threshold for Malathion.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Aquatic life should not be affected unacceptably if the 4-day average concentration of malathion does not exceed 0.028 ug/L (UC Davis Aquatic Life Criteria).

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140684, Malathion	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

262913

Pollutant:

Malathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Aquatic life should not be affected unacceptably if the 4-day average concentration of malathion does not exceed 0.028 ug/L (UC Davis Aquatic Life Criteria).

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: l. Organophosphate insecticides. Reviews of Environmental Contamination and Toxicology 216:1-48.

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140685	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 1 of 25 samples exceeded the 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded.

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140685, Organophosphate Pesticides	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

264137

Pollutant:

Organophosphate Pesticides

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 1 of 25 samples exceeded the water quality threshold for Organophosphorus Pesticides.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for the protection of aquatic life from the additive effects of the organophosphate pesticides chlorpyrifos and diazinon is one toxic unit equivalent. A toxic unit equivalent is equal to the sum of chlorpyrifos and diazinon from a single sample, each having their reported concentration divided their respective evaluation guideline prior to being summed. If this results in a value greater than one, the sample is considered to be in exceedance of the water quality standard. (Bailey et al., 1997).

Guideline Reference:

Joint acute toxicity of Diazinon and Chlorpyrifos to Ceriodaphnia dubia.

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140685, Organophosphate Pesticides	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

264378

Pollutant:

Organophosphate Pesticides

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Joint acute toxicity of Diazinon and Chlorpyrifos to Ceriodaphnia dubia.

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140687	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 140687, PCBs (Polychlorinated biphenyls)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

264538

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for PCBs (Polychlorinated biphenyls). Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The PCB, total aroclors criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.014 ug/L. This value corresponds to the sum of aroclors 1242, 1254, 1221, 1232, 1248, 1260, and 1016 (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140687, PCBs (Polychlorinated biphenyls)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

264465

Pollutant:

PCBs (Polychlorinated biphenyls)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for PCBs (Polychlorinated biphenyls). Although a total of 25 samples were collected, 25 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:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

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: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140693	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 140693, Prometryn	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

265444

Pollutant:

Prometryn

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Prometryn.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Prometryn does not exceed 0.562 ug/L (Bower, et al. 2017).

Guideline Reference:

Water Quality Criteria Report for Prometryn Phase III: Application of the pesticide water quality criteria methodology. Department of Environmental Toxicology. University of California, Davis.

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2010-12-19

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140688	Region 4
Dry Canyon Creek (Ventura County)

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

Regional Board Conclusion:	Insufficient information is available to determine beneficial use support for this waterbody-pollutant combination with the statistical power and confidence required by the Listing Policy. Beneficial use support will be reassessed in a future cycle, if more data are available.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 140688, Simazine	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

266584

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for Simazine.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The evaluation guideline for simazine is the USEPA Aquatic Life Benchmark of 6 ug/L for a nonvascular plant (acute).

Guideline Reference:

OPP Aquatic Life Benchmarks

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2010-12-19

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140678	Region 4
Dry Canyon Creek (Ventura County)

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:	This pollutant is being considered for removal from the CWA section 303(d) List under section 4.1 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against removing this water segment-pollutant combination from the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 0 of 25 samples exceeded the CRITERIA and this exceeds the allowable frequency listed in Table 4.1 of the Listing Policy. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140678, alpha-Endosulfan (Endosulfan 1)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260856

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan I (alpha-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140678, alpha-Endosulfan (Endosulfan 1)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260964

Pollutant:

alpha-Endosulfan (Endosulfan 1)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for Endosulfan I.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan I (alpha-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140686	Region 4
Dry Canyon Creek (Ventura County)

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:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 2 and 0 of 25 samples exceeded the CRITERIA and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 140686, beta-Endosulfan (Endosulfan 2)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260884

Pollutant:

beta-Endosulfan (Endosulfan 2)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 0 of 25 samples exceeded the water quality threshold for Endosulfan II.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan II (beta-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140686, beta-Endosulfan (Endosulfan 2)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

260975

Pollutant:

beta-Endosulfan (Endosulfan 2)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The endosulfan II (beta-endosulfan) criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.056 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-12-19 and 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140691	Region 4
Dry Canyon Creek (Ventura County)

Pollutant:	Bifenthrin
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 1 of 1 and 20 of 20 samples exceed the CRITERIA 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 140691, Bifenthrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

257627

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 20 of the 20 samples exceeded the water quality threshold for Bifenthrin. Although a total of 24 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for bifenthrin is 0.1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of bifenthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Bifenthrin

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140691, Bifenthrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

257874

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Bifenthrin. Although a total of 2 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Bifenthrin

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140695	Region 4
Dry Canyon Creek (Ventura County)

Pollutant:	Cyfluthrin
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Seven of 7 samples exceed the criteria 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 140695, Cyfluthrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

259224

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 7 of the 7 samples exceeded the water quality threshold for Cyfluthrin. Although a total of 24 samples were collected, 17 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for cyfluthrin is 0.2 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cyfluthrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140695, Cyfluthrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

259417

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Cyfluthrin. Although a total of 2 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cyfluthrin

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140692	Region 4
Dry Canyon Creek (Ventura County)

Pollutant:	Cypermethrin
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 0 and 3 of 3 samples exceed the CRITERIA 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 140692, Cypermethrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

259308

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Cypermethrin. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for cypermethrin is 0.3 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of cypermethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140692, Cypermethrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

259246

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 3 of the 3 samples exceeded the water quality threshold for Cypermethrin. Although a total of 24 samples were collected, 21 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Cypermethrin

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140697	Region 4
Dry Canyon Creek (Ventura County)

Pollutant:	Permethrin
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 0 and 4 of 4 samples exceed the CRITERIA 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 140697, Permethrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

264758

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Permethrin. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The chronic criterion for permethrin is 1 ng/L (expressed as a 4-day average). If the freely dissolved concentrations of permethrin were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Water Quality Criteria Report for Permethrin

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140697, Permethrin	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

264970

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 4 of the 4 samples exceeded the water quality threshold for Permethrin. Although a total of 23 samples were collected, 19 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Water Quality Criteria Report for Permethrin

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140690	Region 4
Dry Canyon Creek (Ventura County)

Pollutant:	Pyrethroids
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 1 of 1 and 20 of 20 samples exceed the GUIDELINE 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 140690, Pyrethroids	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

265953

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Pyrethroids. Although a total of 24 samples were collected, 23 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

The summed ratios of the pyrethroid pesticides bifenthrin, cyfluthrin, cypermethrin, esfenvalerate, lambda-cyhalothrin, permethrin and their respective chronic concentration goals are not to exceed 1. If the freely dissolved concentrations of these pesticides were reported or could be calculated then these values were used for this assessment. In the absence of freely dissolved concentrations, total concentrations were used.

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140690, Pyrethroids	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

265914

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and results are as follows: 20 of 20 samples exceeded the water quality threshold for Pyrethroids.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan for the Los Angeles Region states that: No individual pesticide or combination of pesticides shall be present in concentrations that adversely affect beneficial uses.

Objective/Criterion Reference:

Water Quality Control Plan Los Angeles Region R4 Basin Plan

Evaluation Guideline:

Guideline Reference:

Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Pyrethroid Pesticide Discharges

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

The samples were collected between the dates of 2010-11-10 and 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	140689	Region 4
Dry Canyon Creek (Ventura County)

Pollutant:	Toxaphene
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
Expected TMDL Completion Date:	2037
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 0 and 2 of 2 samples exceed the CRITERIA 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 140689, Toxaphene	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

267905

Pollutant:

Toxaphene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) 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 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The toxaphene criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0002 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 140689, Toxaphene	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

267863

Pollutant:

Toxaphene

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 2 of the 2 samples exceeded the water quality threshold for Toxaphene. Although a total of 24 samples were collected, 22 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:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The toxaphene criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.0002 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan


DECISION ID	149528	Region 4
Dry Canyon Creek (Ventura County)

Pollutant:	DDT (Dichlorodiphenyltrichloroethane)
Final Listing Decision:	List on 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	A Source Unknown
TMDL Name:	Calleguas Creek PCBs (7)
TMDL Project Code:	360
Date TMDL Approved by USEPA:	03/24/2006
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. 0 of 0 and 3 of 3 samples exceed the CRITERIA 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:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 149528, DDT (Dichlorodiphenyltrichloroethane)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

259921

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) to determine beneficial use support and the results are as follows: 3 of the 3 samples exceeded the water quality threshold for DDT(p,p'). Although a total of 25 samples were collected, 22 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:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (07T_DC_H).

Temporal Representation:

Data for this waterbody was collected over the date range 2010-11-10 to 2015-05-05

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan

Line of Evidence (LOE) for Decision ID 149528, DDT (Dichlorodiphenyltrichloroethane)	Region 4
Dry Canyon Creek (Ventura County)

LOE ID:

259958

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Calleguas Creek TMDL Work Plan Monitoring data for Dry Canyon Creek (Ventura County) 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 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

WQ data from the California Environmental Data Exchange Network assembled for the 2024 Integrated Report in Region 4.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT(4,4') criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is 0.001 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site: 07T_DC_H (Dry Canyon at Heywood Street).

Temporal Representation:

Data for this waterbody were collected over the date range 2010-12-19 to 2012-01-23

Environmental Conditions:

QAPP Information:

LARRY WALKER ASSOCIATES. 2020. Calleguas Creek Watershed Management Plan.

QAPP Information Reference(s):

Calleguas Creek Watershed Management Plan