Final California 2020 Integrated Report (303(d) List/305(b) Report)

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107212	Region 3
Watsonville Slough

Pollutant:	Aldicarb
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 Clean Water Act (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. A total of two lines of evidence are available in the administrative record to assess this pollutant. Sample and exceedance counts for the lines of evidence with the fraction identified as “none” or “not recorded” are grouped together with those having the fraction “total”, based on the analytical method used. Once summed, a total of zero of three samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. The readily available data and information are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 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. 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. A total of zero of three samples exceed the evaluation guideline for the warm freshwater habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107212, Aldicarb	Region 3
Watsonville Slough

LOE ID:

157302

Pollutant:

Aldicarb

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Aldicarb. Although a total of 1 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Aldicarb is the USEPA Aquatic Life Benchmark of 0.46 ug/L for a fish (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Date for this waterbody was collected over the date range 2014-02-28 to 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107212, Aldicarb	Region 3
Watsonville Slough

LOE ID:

157144

Pollutant:

Aldicarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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 Surface Water Monitoring Project data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Aldicarb.

Data Reference:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Aldicarb is the USEPA Aquatic Life Benchmark of 0.46 ug/L for a fish (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	128097	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Eleven lines of evidence (LOEs) are available in the administrative record to assess this pollutant. Sample and exceedance counts for the lines of evidence with the fraction identified as “none” or “not recorded” are grouped together with those having the fraction “total”, based on the analytical method used. The following is a summary of the sample and exceedances for each beneficial use: Based on LOEs summarizing un-ionized ammonia data, two of the 87 samples exceed the water quality objective (Basin Plan) set to protect aquatic life and one of the 111 samples exceed the water quality objective set to protect Fish Spawning habitat. Based on LOEs summarizing total ammonia data (‘nitrogen, ammonia’ and ‘nitrogen as ammonia’) two of the 44 samples exceed the EPA's Aquatic Life Ambient Water Quality Criteria set to protect aquatic life. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of the 87 un-ionized ammonia samples exceed the water quality objective set to protect aquatic life, one of the 111 un-ionized ammonia samples exceed the water quality objective set to protect fish spawning habitat, and two of the 44 total ammonia samples exceed the criteria set to protect aquatic life, however none of these 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 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

9404

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 12 samples exceed the criterion for Ammonia as N, Unionized.

Data Reference:

Final Data File used for assessment: CCAMP Water Quality Data_file1

Final Data File used for assessment: CCAMP Water Quality Data_file2

Final Data File used for assessment: CCAMP Water Quality Data_file3

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin General Objective, Chapter III, Section II.A.2 (General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries) states that the discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/l (as N) in receiving waters (page III-4) .

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Data was collected over the time period 1/24/2005-3/16/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

219314

Pollutant:

Ammonia (Unionized)

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 SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and the results are as follows: 1 of the 16 samples exceeded the water quality threshold for Ammonia as N, Unionized. Although a total of 20 samples were collected, 4 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin General Objective, Chapter 3, Section 3.3.2 (Objectives for all Inland Surface Waters, Enclosed Bays, and Estuaries) states that the discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/L (as N) in receiving waters (page 32).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-01-12 to 2017-11-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

219288

Pollutant:

Ammonia (Unionized)

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 44 samples exceeded the water quality threshold for Ammonia as N, Unionized.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2010-04-26 and 2018-06-19

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

183823

Pollutant:

Nitrogen, ammonia (Total Ammonia)

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 SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and the results are as follows: 1 of the 12 samples exceeded the water quality threshold for Ammonia as N. Although a total of 13 samples were collected, 1 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The Total Ammonia criterion continuous concentration (expressed as a 30-day average) to protect aquatic life in freshwater is Temperature and pH dependent, and was calculated according to the formula listed in the Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013 document.

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-02-09 to 2017-11-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

149451

Pollutant:

Ammonia (Unionized)

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 Surface Water Monitoring Project data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality standard for Ammonia as N, Unionized. 1 of these samples were estimates.

Data Reference:

CMP water quality data 10/17/2018--12/20/2018.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data were collected from 1 station. Station Code(s): 305WSA

Temporal Representation:

Data for this waterbody were collected on 2018-12-19

Environmental Conditions:

QAPP Information:

Data was collected verified in accordance with the Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program,

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

58976

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

0 of 14 samples exceed the water quality objective for Un-ionized Ammonia (as N). Un-ionized ammonia (as N) was calculated from Total Ammonia (as N) from monthly samples reported in the data. The Un-ionized ammonia (as N) values were then established and compared to the Un-ionized Ammonia (as N) at 0.025 mg/L in the RB3 Basin Plan.

Data Reference:

City of Watsonville Long Term Management Strategy Data, May 2009-Jul. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Region (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations that are toxic to, or that produce detrimental physiological responses in human, plant, animal, or aquatic life. The discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/l (as N) in receiving waters for toxicity.

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at station Watsonville Slough @ Ohlone Parkway Bridge.

Temporal Representation:

Samples were collected monthly from May 2009 to July 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

183990

Pollutant:

Nitrogen, ammonia (Total Ammonia)

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 32 samples exceeded the water quality threshold for Ammonia as N.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2010-05-25 and 2018-06-19

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

58977

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

0 of 33 samples exceed the water quality objective for Un-ionized Ammonia (as N). Un-ionized ammonia (as N) was calculated from Total Ammonia (as N) from monthly samples reported in the data. The Un-ionized ammonia (as N) values were then established and compared to the Un-ionized Ammonia (as N) at 0.025 mg/L in the RB3 Basin Plan.

Data Reference:

City of Watsonville Restoration Project Water Quality Data, Aug. 2004-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at site 2 located at the tip of the peninsula about 300 ft E-NE of the Nature Center. Samples from site 1 are not representative of the water body as a whole and was not counted. Site 1 is cut off from the slough by soil filled-in from construction projects and samples are heavily influenced from effluent from a nearby storm drain.

Temporal Representation:

Pre-restoration samples were collected from January 2005 to July 2005. Post-restoration samples were collected bi-monthly from October 2005 to June 2010.

Environmental Conditions:

QAPP Information:

Data were collected by the City of Watsonville staff for the Upper Watsonville Slough Restoration Project. Samples were analyzed by City of Watsonville laboratory (ELAP #1179) and are consistent with 40 CFR 136 methods.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

58978

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Fish Spawning

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

1 of 64 samples exceed the water quality objective for Un-ionized Ammonia (as N). Un-ionized ammonia (as N) was calculated from Total Ammonia (as N) from monthly samples reported in the data. The Un-ionized ammonia (as N) values were then established and compared to the Un-ionized Ammonia (as N) at 0.025 mg/L in the RB3 Basin Plan.

Data Reference:

City of Watsonville Restoration Project Water Quality Data, Aug. 2004-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected at three sites: 1) at mid-point, south side of road/trail that crosses Watsonville Slough from Ford St., 2) about 30ft. east of Ohlone Parkway, and 3) just east of Lee Rd.

Temporal Representation:

Pre-restoration samples were collected monthly from May 2006 to August 2006. Post-restoration samples were collected bi-monthly from April 2007 to June 2010.

Environmental Conditions:

No samples were collected from the second and third sites during 8/27/2007 because of restoration activities. No samples were collected from the third site during 10/25/2007 because of restoration activities.

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

48892

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Water Board Staff assessed public submissions data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 12 samples exceed the criterion for Ammonia as N, Unionized.

Data Reference:

Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSAxxx - Watsonville Slough upstream Harkins Slough]

Temporal Representation:

Data was collected over the time period 4/27/2009-3/30/2010.

Environmental Conditions:

Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 128097, Ammonia	Region 3
Watsonville Slough

LOE ID:

13674

Pollutant:

Ammonia (Unionized)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for Ammonia as N, Unionized.

Data Reference:

Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data

Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Data was collected over the time period 2/21/2006-3/28/2006. Cooperative Monitoring Program (CMP) staff conduct monitoring for conventional pollutants at all Ag Waiver monitoring sites monthly. CMP staff also conduct water toxicity monitoring quarterly and sediment toxicity monitoring annually (in spring).

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):


DECISION ID	107156	Region 3
Watsonville Slough

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

Regional Board Conclusion:	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. LOE 94160 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the ten samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107156, Atrazine	Region 3
Watsonville Slough

LOE ID:

224887

Pollutant:

Atrazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Atrazine.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of <1 ug/L for a nonvascular plant (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107156, Atrazine	Region 3
Watsonville Slough

LOE ID:

158611

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Atrazine is the USEPA Aquatic Life Benchmark of <1 ug/L for a nonvascular plant (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107172	Region 3
Watsonville Slough

Pollutant:	Azinphos-methyl (Guthion)
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107172, Azinphos-methyl (Guthion)	Region 3
Watsonville Slough

LOE ID:

159055

Pollutant:

Azinphos-methyl (Guthion)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The Criterion Continuous Concentration for freshwater aquatic life is 0.01 ug/L (National Recommended Water Quality Criteria, EPA 2016)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107225	Region 3
Watsonville Slough

Pollutant:	Bensulide
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 Clean Water Act (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. A total of one line of evidence is available in the administrative record to assess this pollutant. A total of zero of three samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. The readily available data and information are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 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. 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. A total of zero of three samples exceed the evaluation guideline for the warm freshwater habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 107225, Bensulide	Region 3
Watsonville Slough

LOE ID:

159046

Pollutant:

Bensulide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Bensulide is the USEPA Aquatic Life Benchmark of 11 ug/L for an invertebrate (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	107202	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 at least one line of evidence is necessary to assess listing status, but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the section 303(d) List. Six lines of evidence are available in the administrative record to assess this pollutant. Zero of nine sediment samples exceed the evaluation guideline and zero of nine water samples exceed the evaluation guideline used to interpret the narrative water quality objective for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107202, Bifenthrin	Region 3
Watsonville Slough

LOE ID:

94161

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for BIFENTHRIN.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The genus mean acute value for a mysid (Mysidopsis bahia) of 0.0034 ug/L (DFG 00-6, 2000).

Guideline Reference:

Hazard Assessment of the Synthetic Pyrethroid Insecticides Bifenthrin, Cypermethrin, Esfenvalerate, and Permethrin to Aquatic Organisms in the Sacramento-San Joaquin River System. California Department of Fish and Game. Office of Spill Prevention and Response, Administrative Report 00-6

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107202, Bifenthrin	Region 3
Watsonville Slough

LOE ID:

94162

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for BIFENTHRIN.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of bifenthrin does not exceed 0.0006 ug/L and if the 1-h average concentration does not exceed 0.004 ug/L. Mixtures of bifenthrin and other pyrethroids should be considered in an additive manner. (Fojut et al. 2012)

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: ll. Pyrethroid insecticides. Reviews of Environmental Contamination and Toxicology 216:51-103.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107202, Bifenthrin	Region 3
Watsonville Slough

LOE ID:

58986

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Bifenthrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for bifenthrin is the median lethal concentration (LC50) of 0.43 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.43 ug/g is the geometric mean of three toxicity LC50 values from Amweg et al. (2005) and one toxicity LC50 value from Amweg and Weston (2007).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107202, Bifenthrin	Region 3
Watsonville Slough

LOE ID:

94035

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Bifenthrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107202, Bifenthrin	Region 3
Watsonville Slough

LOE ID:

151561

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and the results are as follows: 1 of the 3 samples exceeded the evaluation guideline for Bifenthrin .

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for bifenthrin is the median lethal concentration (LC50) of 0.43 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.43 ug/g is the geometric mean of LC50 values for bifenthrin from Amweg et al. (2005) and Amweg and Weston (2007).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107202, Bifenthrin	Region 3
Watsonville Slough

LOE ID:

151620

Pollutant:

Bifenthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the evaluation guideline for Bifenthrin .

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for bifenthrin is the median lethal concentration (LC50) of 0.43 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.43 ug/g is the geometric mean of LC50 values for bifenthrin from Amweg et al. (2005) and Amweg and Weston (2007).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	129875	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. LOE 94163 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 129875, Butylate	Region 3
Watsonville Slough

LOE ID:

224970

Pollutant:

Butylate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Butylate.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Butylate is the USEPA Aquatic Life Benchmark of 105 ug/L for a fish (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107157	Region 3
Watsonville Slough

Pollutant:	Cadmium
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107157, Cadmium	Region 3
Watsonville Slough

LOE ID:

159729

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107157, Cadmium	Region 3
Watsonville Slough

LOE ID:

160305

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion continuous concentrations to protect aquatic life in saltwater. The criterion in saltwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107157, Cadmium	Region 3
Watsonville Slough

LOE ID:

159660

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Cadmium.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107157, Cadmium	Region 3
Watsonville Slough

LOE ID:

159984

Pollutant:

Cadmium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	107158	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. One of the thirteen samples exceed the evaluation guideline used to interpret the narrative water quality objective for the protection of aquatic life. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of the thirteen samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. Moreover, this sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107158, Carbaryl	Region 3
Watsonville Slough

LOE ID:

94164

Pollutant:

Carbaryl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceed the criterion for CARBARYL.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The USEPA national ambient water quality criteria for freshwater aquatic life instantaneous maximum for carbaryl is 0.02 µg/L.

Guideline Reference:

Compilation of Water Quality Goals

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107158, Carbaryl	Region 3
Watsonville Slough

LOE ID:

160717

Pollutant:

Carbaryl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The Criterion Continuous Concentration for freshwater aquatic life is 2.1 ug/L (National Recommended Water Quality Criteria, EPA 2016)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 107158, Carbaryl	Region 3
Watsonville Slough

LOE ID:

160742

Pollutant:

Carbaryl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The Criterion Continuous Concentration for freshwater aquatic life is 2.1 ug/L (National Recommended Water Quality Criteria, EPA 2016)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107159	Region 3
Watsonville Slough

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

Regional Board Conclusion:	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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107159, Carbofuran	Region 3
Watsonville Slough

LOE ID:

160676

Pollutant:

Carbofuran

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Carbofuran is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertibrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107159, Carbofuran	Region 3
Watsonville Slough

LOE ID:

94165

Pollutant:

Carbofuran

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for CARBOFURAN.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The USEPA national ambient water quality criteria for freshwater aquatic life instantaneous maximum for carbofuran is 0.5 µg/L.

Guideline Reference:

Hazard Assessment of the Insecticide Carbofuran to Aquatic Organisms in the Sacramento River System

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107159, Carbofuran	Region 3
Watsonville Slough

LOE ID:

160444

Pollutant:

Carbofuran

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Carbofuran is the USEPA Aquatic Life Benchmark of 0.75 ug/L for an invertibrate (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	107160	Region 3
Watsonville Slough

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:	This pollutant is being considered for placement on the Clean Water Act (CWA) section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the CWA section 303(d) List. A total of two lines of evidence are available in the administrative record to assess this pollutant. A total of zero of one samples exceed the evaluation guideline for the estuarine habitat beneficial use and zero of one samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. These data are insufficient to determine the applicable beneficial use support rating with the power and confidence required by the Listing Policy. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed 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. A total of zero of one samples exceed the evaluation guideline for the estuarine habitat beneficial use and zero of one samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107160, Chlordane	Region 3
Watsonville Slough

LOE ID:

152068

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Chlordane from MacDonald et al., 2000a which states that the probable effect concentration for Chlordane is 17.6 ug/kg. (dw = Dry Weight)

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107160, Chlordane	Region 3
Watsonville Slough

LOE ID:

151840

Pollutant:

Chlordane

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline used in this assessment comes from Long and Morgan, 1990, and is the Effects Range Median (ERM) value of 6 ng/g DW

Guideline Reference:

The potential for biological effects of sediment-sorbed contaminants tested in the National Status of Trends Program. NOAA Technical Memorandum NOS OMA 52. Seattle, WA: National Oceanic and Atmospheric Administration

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107223	Region 3
Watsonville Slough

Pollutant:	Clothianidin
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107223, Clothianidin	Region 3
Watsonville Slough

LOE ID:

162311

Pollutant:

Clothianidin

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 2 samples exceeded the water quality threshold for Clothianidin.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Clothianidin is the USEPA Aquatic Life Benchmark of 0.05 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107207	Region 3
Watsonville Slough

Pollutant:	Cyanazine
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 107207, Cyanazine	Region 3
Watsonville Slough

LOE ID:

163345

Pollutant:

Cyanazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for cyanazine is the EC50 of 4.8 ug/L for Navicula pelliculosa (freshwater diatom) (USEPA Office of Pesticide Programs Ecotoxicity database).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107214	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the Section 303(d) List. Four lines of evidence are available in the administrative record to assess this pollutant. Zero of the 18 sediment samples exceed the evaluation guideline applied to protect for aquatic life beneficial uses. 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. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the 18 sediment samples exceed the evaluation guideline applied to protect for aquatic life beneficial uses 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.

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 107214, Cyfluthrin	Region 3
Watsonville Slough

LOE ID:

152163

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for cyfluthrin is the median lethal concentration (LC50) of 1.1 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1.1 ug/g is the geometric mean of LC50 values for cyfluthrin from Amweg et al. (2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107214, Cyfluthrin	Region 3
Watsonville Slough

LOE ID:

58857

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Cyfluthrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107214, Cyfluthrin	Region 3
Watsonville Slough

LOE ID:

152105

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and the results are as follows: 0 of the 3 samples exceeded the evaluation guideline for Cyfluthrin, total .

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107214, Cyfluthrin	Region 3
Watsonville Slough

LOE ID:

94063

Pollutant:

Cyfluthrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 20 samples exceed the criterion for Cyfluthrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	107216	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 at one line of evidence are necessary to assess listing status but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the Section 303(d) list. Three lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine water samples exceed the evaluation guideline for aquatic life protection. Zero of the twelve sediment samples exceed the evaluation guideline used to protect aquatic life beneficial uses. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. Based on the readily available data and information, the weight of evidence indicates that even though this water body is impaired for sediment toxicity these water body-pollutant combinations should not be placed on the section 303(d) list because applicable water quality standards for these pollutants are not being exceeded. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107216, Cyhalothrin, Lambda	Region 3
Watsonville Slough

LOE ID:

152663

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for lambda-cyhalothrin is the median lethal concentration (LC50) of 0.44 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.44 ug/g is the geometric mean of LC50 values for lambda-cyhalothrin from Amweg et al. (2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107216, Cyhalothrin, Lambda	Region 3
Watsonville Slough

LOE ID:

152449

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107216, Cyhalothrin, Lambda	Region 3
Watsonville Slough

LOE ID:

94168

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Cyhalothrin, Lambda.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of Cyhalothrin, lambda, total does not exceed 0.0005 ug/L.

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: ll. Pyrethroid insecticides. Reviews of Environmental Contamination and Toxicology 216:51-103.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107216, Cyhalothrin, Lambda	Region 3
Watsonville Slough

LOE ID:

94037

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 3 - Central Coast Region staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Cyhalothrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107216, Cyhalothrin, Lambda	Region 3
Watsonville Slough

LOE ID:

58861

Pollutant:

Cyhalothrin, Lambda

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Cyhalothrin, lambda, total.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	107203	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 at least one line of evidence is necessary to assess listing status, but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the section 303(d) List. Five lines of evidence are available in the administrative record to assess this pollutant. Zero of 13 sediment samples exceed the evaluation guideline and zero of nine water samples exceed the evaluation guideline used to interpret the narrative water quality objective for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107203, Cypermethrin	Region 3
Watsonville Slough

LOE ID:

94038

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Cypermethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for cypermethrin is the median lethal concentration (LC50) of 0.3 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.3 ug/g is the geometric mean of LC50 values for cypermethrin from Maund et al. (2002).

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107203, Cypermethrin	Region 3
Watsonville Slough

LOE ID:

94169

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for CYPERMETHRIN.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The genus mean acute value for a grass shrimp (Palaemonetes pugio) of 0.016 ug/L (DFG 00-6, 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107203, Cypermethrin	Region 3
Watsonville Slough

LOE ID:

94170

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for CYPERMETHRIN.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of cypermethrin does not exceed 0.0002 ug/L and if the 1-h average concentration does not exceed 0.001 ug/L. Mixtures of cypermethrin and other pyrethroids should be considered in an additive manner. (Fojut et al. 2012)

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: ll. Pyrethroid insecticides. Reviews of Environmental Contamination and Toxicology 216:51-103.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107203, Cypermethrin	Region 3
Watsonville Slough

LOE ID:

152733

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107203, Cypermethrin	Region 3
Watsonville Slough

LOE ID:

152875

Pollutant:

Cypermethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	130086	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the 303(d) List. Four lines of evidence are available in the administrative record to assess this pollutant. Four LOEs summarize sediment samples. One of 17 sediment samples exceed the DDD evaluation guideline (MacDonald et al., 2000a) set to protect for aquatic life beneficial uses. The data support the conclusion that the aquatic life beneficial use is fully supported. 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. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 17 sediment samples, exceed the evaluation guidelines 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 130086, DDD (Dichlorodiphenyldichloroethane)	Region 3
Watsonville Slough

LOE ID:

58868

Pollutant:

DDD (Dichlorodiphenyldichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for DDD.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDD is 28.0 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 130086, DDD (Dichlorodiphenyldichloroethane)	Region 3
Watsonville Slough

LOE ID:

94049

Pollutant:

DDD (Dichlorodiphenyldichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 11 samples exceed the criterion for DDD.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDD is 28.0 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 130086, DDD (Dichlorodiphenyldichloroethane)	Region 3
Watsonville Slough

LOE ID:

58869

Pollutant:

DDD (Dichlorodiphenyldichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for DDD. Data assessed were suspended sediment samples isolated from the whole water sample.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDD is 28.0 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-2/16/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 130086, DDD (Dichlorodiphenyldichloroethane)	Region 3
Watsonville Slough

LOE ID:

153120

Pollutant:

DDD (Dichlorodiphenyldichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Sum DDD from MacDonald et al., 2000a which states that the probable effect concentration for Sum DDD is 28 ug/kg. (dw = Dry Weight)

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	129996	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the 303(d) List. Ten lines of evidence are available in the administrative record to assess this pollutant. Note that this decision combines the pollutant ‘DDT’ and ‘total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD).’ Two LOEs summarize water samples. Zero of nine water samples exceed the DDT evaluation guideline (California Toxics Rule, 2000), set to protect for aquatic life and estuarine habitat beneficial uses. Eight LOEs summarize sediment samples. One of 17 sediment samples exceed the DDT evaluation guideline (MacDonald et al., 2000a) set to protect for aquatic life beneficial uses. One of 17 sediment samples exceed the total DDT evaluation guideline (MacDonald et al., 2000a) set to protect for aquatic life beneficial uses. 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. For the water matrix, 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. However, for the sediment matrix, the data support the conclusion that the aquatic life beneficial use is fully supported. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero out of nine water samples, and one of the 17 sediment samples, exceed the evaluation guidelines 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 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

153208

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Sum DDT from MacDonald et al., 2000a which states that the probable effect concentration for Sum DDT is 62.9 ug/kg. (dw = Dry Weight)

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

155750

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Total DDTs from MacDonald et al., 2000a which states that the probable effect concentration for Total DDTs is 572 ug/kg. (dw = Dry Weight)

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

58983

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for DDT, Total.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for total DDTs is 572 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

94047

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 11 samples exceed the criterion for DDT, Total.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for total DDTs is 572 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

58989

Pollutant:

Total DDT (sum of 4,4'- and 2,4'- isomers of DDT, DDE, and DDD)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for DDT, Total. Data assessed were suspended sediment samples isolated from the whole water sample.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for total DDTs is 572 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-2/16/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

94183

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:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for p p' DDT.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The DDT 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:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

58876

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for DDT.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDT is 62.9 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

94083

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 11 samples exceed the criterion for DDT.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDT is 62.9 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

58880

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for DDT. Data assessed were suspended sediment samples isolated from the whole water sample.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In freshwater sediments the probable effect concentration (predictive of sediment toxicity) for sum of DDT is 62.9 ug/Kg dry weight (MacDonald et al. 2000).

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-2/16/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 129996, DDT (Dichlorodiphenyltrichloroethane)	Region 3
Watsonville Slough

LOE ID:

94182

Pollutant:

DDT (Dichlorodiphenyltrichloroethane)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for p p' DDT.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

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

Objective/Criterion Reference:

Code of Federal Regulations 40 part 131.38 Establishment of numeric criteria for priority toxic pollutants for the State of California. 7/1/2011 Edition

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA


DECISION ID	129872	Region 3
Watsonville Slough

Pollutant:	Dacthal
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. One line of evidence is available in the administrative record to assess this pollutant. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 129872, Dacthal	Region 3
Watsonville Slough

LOE ID:

225010

Pollutant:

Dacthal

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Dacthal.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Dacthal is the USEPA Aquatic Life Benchmark of >1100 ug/L for a nonvascular plant (acute) and vascular plant (acute). The benchmark was derived from a \greater-than\" value (for example, > 265,000) and may overestimate toxicity."

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107215	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status, but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the section 303(d) List. Five lines of evidence are available in the administrative record to assess this pollutant. LOE 94171 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is none or not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight water samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). Zero of the fourteen sediment samples exceed the evaluation guidelines for aquatic life protection. These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107215, Deltamethrin	Region 3
Watsonville Slough

LOE ID:

225109

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Deltamethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Deltamethrin is the USEPA Aquatic Life Benchmark of 0.0041 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107215, Deltamethrin	Region 3
Watsonville Slough

LOE ID:

153619

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for deltamethrin is the median lethal concentration (LC50) of 0.79 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 0.79 ug/g is the geometric mean of LC50 values for deltamethrin from Amweg et al. (2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107215, Deltamethrin	Region 3
Watsonville Slough

LOE ID:

153565

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107215, Deltamethrin	Region 3
Watsonville Slough

LOE ID:

58882

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Deltamethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107215, Deltamethrin	Region 3
Watsonville Slough

LOE ID:

94040

Pollutant:

Deltamethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Deltamethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	107164	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the Section 303(d) List. Eleven lines of evidence are available in the administrative record to assess this pollutant. One of 20 water samples exceeded the aquatic life evaluation guideline (Finlayson, 2004). For lines of evidence where the fraction is none staff assumed that the fraction is total, based on the analytical method, and the sample and exceedance counts are summed for both fractions for the purpose of making this decision. This sample size is sufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating of fully supporting. A minimum of 16 samples is needed to determine if a beneficial use is supported using table 3.1. One of 15 water samples exceed the evaluation guideline for estuarine beneficial use (National Recommended Water Quality Criteria, EPA 2016) and zero of two sediment samples exceeded the aquatic life evaluation guideline. These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported using table 3.1. 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. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of 20 water samples exceed the evaluation guidelines for aquatic life and this sample size is sufficient to determine the aquatic life beneficial use support rating of fully supporting. One of 15 water samples exceed the evaluation guideline for the estuarine beneficial use and zero of 12 sediment samples exceed the evaluation guideline for aquatic life beneficial use and these sample sizes are insufficient to determine the beneficial use support rating. 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 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

94041

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Diazinon.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for diazinon is the median lethal concentration (LC50) of 11 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 11 ug/g is the geometric mean of LC50 values for diazinon from Ding et al. (2011).

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

94172

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceed the criterion for DIAZINON.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).

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:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

16753

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: SWAMP Toxicity Data 2001-06

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Objective/Criterion Reference:

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

Evaluation Guideline:

One hour average maximum concentration 0.16 ug/L as stated in Sipmann and Finlayson (2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA001 - Watsonville Slough above pump station at San Andreas]

Temporal Representation:

Data was collected over the time period 1/12/2006-5/30/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

18695

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Regional Board Staff assessed Department of Health Services (R3_DHS1) data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceed the criterion for diazinon.

Data Reference:

Final Data File used for assessment: DHS Sediment Chemistry Data, File 1 (feb06)

Final Data File used for assessment: DHS Sediment Chemistry Data, File 2 (sed06)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Objective/Criterion Reference:

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

Evaluation Guideline:

One hour average maximum concentration 0.16 ug/L as stated in Sipmann and Finlayson (2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA_DHS - Watsonville Slough]

Temporal Representation:

Data was collected over the time period 12/13/1994-1/27/1995.

Environmental Conditions:

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

QAPP Information:

No QAPP was provided for this data set.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

94173

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceed the criterion for DIAZINON.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (Finlayson, 2004).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

16659

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: SWAMP Toxicity Data 2001-06

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Objective/Criterion Reference:

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

Evaluation Guideline:

One hour average maximum concentration 0.16 ug/L as stated in Sipmann and Finlayson (2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA001 - Watsonville Slough above pump station at San Andreas]

Temporal Representation:

Data was collected on a single day 5/3/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

58883

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Diazinon.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

163789

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (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

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

163788

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The Criterion Continuous Concentration for saltwater aquatic life is 0.82 ug/L (National Recommended Water Quality Criteria, EPA 2016)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

163494

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The freshwater chronic value for diazinon is 0.1 ug/L, expressed as a continuous concentration (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

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107164, Diazinon	Region 3
Watsonville Slough

LOE ID:

163791

Pollutant:

Diazinon

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The Criterion Continuous Concentration for saltwater aquatic life is 0.82 ug/L (National Recommended Water Quality Criteria, EPA 2016)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	107165	Region 3
Watsonville Slough

Pollutant:	Dichlorvos
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 107165, Dichlorvos	Region 3
Watsonville Slough

LOE ID:

164470

Pollutant:

Dichlorvos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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 Surface Water Monitoring Project data for Watsonville Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 3 samples were collected, 3 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE).

Temporal Representation:

Date for this waterbody was collected over the date range 2011-04-26 to 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107165, Dichlorvos	Region 3
Watsonville Slough

LOE ID:

164394

Pollutant:

Dichlorvos

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support, and the results are as follows: 0 of the 0 samples exceeded the evaluation guideline for Dichlorvos. Although a total of 2 samples were collected, 2 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Dichlorvos is the USEPA Aquatic Life Benchmark of 0.0058 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Date for this waterbody was collected over the date range 2017-12-13 to 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107166	Region 3
Watsonville Slough

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 sections 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity. Two lines of evidence are available in the administrative record to assess this pollutant. The single sediment sample exceeded the evaluation guideline for aquatic life beneficial uses. However, this sample size is insufficient to determine an applicable beneficial use support rating with the power and confidence of the Listing Policy. In accordance with Table 3.1 of the Listing Policy, a minimum of 16 samples is needed to determine if a beneficial use is fully supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One sediment sample exceeded the evaluation guideline for aquatic life protection 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107166, Dieldrin	Region 3
Watsonville Slough

LOE ID:

153397

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Dieldrin from MacDonald et al., 2000a which states that the probable effect concentration for Dieldrin is 61.8 ug/kg dw. (dw = Dry Weight)

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107166, Dieldrin	Region 3
Watsonville Slough

LOE ID:

153652

Pollutant:

Dieldrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In marine and estuarine sediments the effects range median (predictive of sediment toxicity for sediment-dwelling organisms) for Dieldrin is 8 ng/g dry weight (Long et al., 1995).

Guideline Reference:

Development and evaluation of sediment quality guidelines for Florida coastal waters. Ecotoxicology 5: 253-278

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107205	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under sections 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. For lines of evidence where the fraction is “not recorded” staff assumed that the fraction is “total” and the sample and exceedance counts are summed for the purpose of making this decision. Zero of six water samples exceeded the USEPA aquatic life evaluation guideline. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported using table 3.1. 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. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero samples exceed the evaluation guidelines. 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107205, Dimethoate	Region 3
Watsonville Slough

LOE ID:

164692

Pollutant:

Dimethoate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107205, Dimethoate	Region 3
Watsonville Slough

LOE ID:

164846

Pollutant:

Dimethoate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Dimethoate is the USEPA Aquatic Life Benchmark of 0.5 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107167	Region 3
Watsonville Slough

Pollutant:	Dinitro-o-cresol
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 107167, Dinitro-o-cresol	Region 3
Watsonville Slough

LOE ID:

165152

Pollutant:

Dinitro-o-cresol

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Human health risk associated with organism consumption is 765 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-04-27 and 2017-04-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107168	Region 3
Watsonville Slough

Pollutant:	Disulfoton
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107168, Disulfoton	Region 3
Watsonville Slough

LOE ID:

165482

Pollutant:

Disulfoton

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Disulfoton is the USEPA Aquatic Life Benchmark of 0.01 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107169	Region 3
Watsonville Slough

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107169, Diuron	Region 3
Watsonville Slough

LOE ID:

165614

Pollutant:

Diuron

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Aquatic life should not be affected unacceptably if the 4-day average concentration of Diuron, 1.3 ug/L, is not exceeded more than once every three years on the average (Fojut et al., 2010).

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: III. Diuron. Reviews of Environmental Contamination and Toxicology 216:105-141.

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107170	Region 3
Watsonville Slough

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:	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 107170, Endrin	Region 3
Watsonville Slough

LOE ID:

153700

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In marine and estuarine sediments the sediment quality guideline (predictive of sediment toxicity for sediment-dwelling organisms) for Endrin is 0.76 ug/g OC (USEPA1993d). OC = Organic Carbon

Guideline Reference:

Technical basis for deriving sediment criteria for nonionic organic contaminants for the protection of benthic organisms by using equilibrium partitioning. EPA822-R-93-011. Washington, D.C.: Office of Water, USEPA

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107170, Endrin	Region 3
Watsonville Slough

LOE ID:

153939

Pollutant:

Endrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Endrin from MacDonald et al., 2000a which states that the probable effect concentration for Endrin is 207 ug/kg. (dw = Dry Weight)

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107218	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 at least one line of evidence is necessary to assess listing status, but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the section 303(d) List. Five lines of evidence are available in the administrative record to assess this pollutant. Zero of 14 sediment samples exceed the evaluation guideline and zero of nine water samples exceed the evaluation guideline used to interpret the narrative water quality objective for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107218, Esfenvalerate/Fenvalerate	Region 3
Watsonville Slough

LOE ID:

94042

Pollutant:

Esfenvalerate

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Esfenvalerate.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for esfenvalerate/fenvalerate is the median lethal concentration (LC50) of 1.5 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1.5 ug/g is the geometric mean of LC50 values for esfenvalerate/fenvalerate from Amweg et al. (2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107218, Esfenvalerate/Fenvalerate	Region 3
Watsonville Slough

LOE ID:

153882

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107218, Esfenvalerate/Fenvalerate	Region 3
Watsonville Slough

LOE ID:

58906

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Esfenvalerate.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107218, Esfenvalerate/Fenvalerate	Region 3
Watsonville Slough

LOE ID:

154256

Pollutant:

Esfenvalerate/Fenvalerate

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107218, Esfenvalerate/Fenvalerate	Region 3
Watsonville Slough

LOE ID:

94174

Pollutant:

Esfenvalerate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for ESFENVALERATE.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for esfenvalerate/fenvalerate is the median lethal concentration (LC50) of 1.13 ug/L, as determined in a 96 hour toxicity test using the fathead minnow, Pimephales promelas. (USEPA OPP Ecotoxicity database)

Guideline Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):


DECISION ID	107208	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. LOE 94175 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the nine samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107208, Ethalfluralin	Region 3
Watsonville Slough

LOE ID:

225023

Pollutant:

Ethalfluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Ethalfluralin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Ethalfluralin is the USEPA Aquatic Life Benchmark of 0.4 ug/L for a fish (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107208, Ethalfluralin	Region 3
Watsonville Slough

LOE ID:

165907

Pollutant:

Ethalfluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Ethalfluralin is the USEPA Aquatic Life Benchmark of 0.4 ug/L for a fish (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-06-14 and 2011-06-14

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	107209	Region 3
Watsonville Slough

Pollutant:	Ethoprop
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 Clean Water Act (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. A total of one line of evidence is available in the administrative record to assess this pollutant. A total of zero of three samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. These data are insufficient to determine the applicable beneficial use support rating with the power and confidence required by the Listing Policy. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed 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. A total of zero of three samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107209, Ethoprop	Region 3
Watsonville Slough

LOE ID:

166034

Pollutant:

Ethoprop

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Ethoprop is the USEPA Aquatic Life Benchmark of 0.8 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	107217	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Five lines of evidence are available in the administrative record to assess this pollutant. LOE 94176 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is none or not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. Zero of the 16 sediment samples exceed the evaluation guidelines for aquatic life protection. 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. Zero of the samples exceed the evaluation guidelines 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 107217, Fenpropathrin	Region 3
Watsonville Slough

LOE ID:

154272

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for fenpropathrin is the median lethal concentration (LC50) of 1 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 1 ug/g is the geometric mean of LC50 values for fenpropathrin from Ding et al. ( 2011).

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107217, Fenpropathrin	Region 3
Watsonville Slough

LOE ID:

225439

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Fenpropathrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Fenpropathrin is the USEPA Aquatic Life Benchmark of 0.06 ug/L for a fish (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107217, Fenpropathrin	Region 3
Watsonville Slough

LOE ID:

154018

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107217, Fenpropathrin	Region 3
Watsonville Slough

LOE ID:

58916

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Fenpropathrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107217, Fenpropathrin	Region 3
Watsonville Slough

LOE ID:

94048

Pollutant:

Fenpropathrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Fenpropathrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	107171	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the Clean Water Act (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. A total of one line of evidence is available in the administrative record to assess this pollutant. A total of zero of two samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. The readily available data and information are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 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. 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. A total of zero of two samples exceed the evaluation guideline for the warm freshwater habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107171, Glyphosate	Region 3
Watsonville Slough

LOE ID:

166944

Pollutant:

Glyphosate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Glyphosate is the USEPA Aquatic Life Benchmark of 11900 ug/L for a vascular plant (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	129879	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. LOE 94177 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 129879, Hexazinone	Region 3
Watsonville Slough

LOE ID:

225167

Pollutant:

Hexazinone

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Hexazinone.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Hexazinone is the USEPA Aquatic Life Benchmark of 7 ug/L for a nonvascular plant (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107173	Region 3
Watsonville Slough

Pollutant:	Lead
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. Under section 3.1 at least one line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Zero of the six dissolved lead samples exceed the evaluation guidelines for the aquatic life beneficial uses. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information.' 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. Zero of the samples exceed the evaluation guidelines 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107173, Lead	Region 3
Watsonville Slough

LOE ID:

167965

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107173, Lead	Region 3
Watsonville Slough

LOE ID:

167944

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107173, Lead	Region 3
Watsonville Slough

LOE ID:

167666

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107173, Lead	Region 3
Watsonville Slough

LOE ID:

167746

Pollutant:

Lead

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	107174	Region 3
Watsonville Slough

Pollutant:	Lindane/gamma Hexachlorocyclohexane (gamma-HCH)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	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 107174, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 3
Watsonville Slough

LOE ID:

154499

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Lindane from MacDonald et al., 2000a which states that the probable effect concentration for Lindane is 4.99 ug/kg. (dw = Dry Weight)

Guideline Reference:

Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Environmental Contamination and Toxicology. 39: 20-31

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107174, Lindane/gamma Hexachlorocyclohexane (gamma-HCH)	Region 3
Watsonville Slough

LOE ID:

154907

Pollutant:

Lindane/gamma Hexachlorocyclohexane (gamma-HCH)

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

In marine and estuarine sediments the sediment quality guideline (predictive of sediment toxicity for sediment-dwelling organisms) for HCH, gamma(Lindane; BHC, gamma) is 0.37 ug/g oc (Fairey et al., 2001). OC = Organic Carbon

Guideline Reference:

An evaluation of methods for calculating mean sediment quality guideline quotients as indicators of contamination and acute toxicity to amphipods by chemical mixtures. Environmental Toxicology and Chemistry. 20(10): 2276-2286

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2010-05-25

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107175	Region 3
Watsonville Slough

Pollutant:	Linuron
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 Clean Water Act (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. A total of one line of evidence is available in the administrative record to assess this pollutant. A total of zero of one sample exceeds the evaluation guideline for the warm freshwater habitat beneficial use. The readily available data and information are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 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. 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. A total of zero of one sample exceeds the evaluation guideline for the warm freshwater habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 107175, Linuron	Region 3
Watsonville Slough

LOE ID:

168044

Pollutant:

Linuron

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 RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality threshold for Linuron. 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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Linuron is the USEPA Aquatic Life Benchmark of 0.09 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Data for this waterbody was collected over the date range 2014-02-28 to 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	130783	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Two LOEs summarize water samples: - Zero of three water samples exceed the mercury evaluation guideline (National Recommended Water Quality Criteria, EPA 2016), set to protect for aquatic life beneficial uses. - Zero of three water samples exceed the mercury evaluation guideline (California Toxics Rule, 2000), set to protect for the commercial or recreational collection of fish, shellfish, or organisms beneficial use. 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. 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. No water samples exceeded the evaluation guidelines, 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 130783, Mercury	Region 3
Watsonville Slough

LOE ID:

169499

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Waters shall not contain concentrations of chemical constituents known to be deleterious to fish or wildlife (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The Criterion Continuous Concentration for freshwater aquatic life is 0.77 ug/L (National Recommended Water Quality Criteria, EPA 2016)

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 130783, Mercury	Region 3
Watsonville Slough

LOE ID:

168796

Pollutant:

Mercury

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Human health risk associated with organism consumption is 0.051 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	107154	Region 3
Watsonville Slough

Pollutant:	Methamidophos
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 107154, Methamidophos	Region 3
Watsonville Slough

LOE ID:

169493

Pollutant:

Methamidophos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methamifophos is the USEPA Aquatic Life Benchmark of 4.5 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107204	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. LOE 94179 have been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the 13 samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107204, Methidathion	Region 3
Watsonville Slough

LOE ID:

225360

Pollutant:

Methidathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Methidathion.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107204, Methidathion	Region 3
Watsonville Slough

LOE ID:

169562

Pollutant:

Methidathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107204, Methidathion	Region 3
Watsonville Slough

LOE ID:

169848

Pollutant:

Methidathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methidathion is the USEPA Aquatic Life Benchmark of 0.66 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107199	Region 3
Watsonville Slough

Pollutant:	Methiocarb
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 Clean Water Act (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. A total of two lines of evidence are available in the administrative record to assess this pollutant. Sample and exceedance counts for the lines of evidence with the fraction identified as “none” or “not recorded” are grouped together with those having the fraction “total”, based on the analytical method used. Once summed, a total of zero of four samples exceed the evaluation guideline for the warm freshwater habitat beneficial use. The readily available data and information are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 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. 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. A total of zero of four samples exceed the evaluation guideline for the warm freshwater habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107199, Methiocarb	Region 3
Watsonville Slough

LOE ID:

170076

Pollutant:

Methiocarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methiocarb is the USEPA Aquatic Life Benchmark of 2.75 ug/L for a invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107199, Methiocarb	Region 3
Watsonville Slough

LOE ID:

169877

Pollutant:

Methiocarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methiocarb is the USEPA Aquatic Life Benchmark of 2.75 ug/L for a invertebrate (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	107200	Region 3
Watsonville Slough

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107200, Methomyl	Region 3
Watsonville Slough

LOE ID:

169870

Pollutant:

Methomyl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methomyl is the USEPA Aquatic Life Benchmark of 0.7 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107200, Methomyl	Region 3
Watsonville Slough

LOE ID:

170134

Pollutant:

Methomyl

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Methomyl is the USEPA Aquatic Life Benchmark of 0.7 ug/L for an invertebrate (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	129876	Region 3
Watsonville Slough

Pollutant:	Metolachlor
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. One line of evidence are available in the administrative record to assess this pollutant. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 129876, Metolachlor	Region 3
Watsonville Slough

LOE ID:

225471

Pollutant:

Metolachlor

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Metolachlor.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Metolachlor is the USEPA Aquatic Life Benchmark of 1 ug/L for an invertebrate (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	129873	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. LOE 94180 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 129873, Molinate	Region 3
Watsonville Slough

LOE ID:

225216

Pollutant:

Molinate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Molinate.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Molinate is the USEPA Aquatic Life Benchmark of 105 ug/L for a fish (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	129877	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. LOE 94181 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 129877, Napropamide	Region 3
Watsonville Slough

LOE ID:

225304

Pollutant:

Napropamide

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Napropamide.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Napropamide is the USEPA Aquatic Life Benchmark of 1100 ug/L for a invertebrate (acute) and fish (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107182	Region 3
Watsonville Slough

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 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. Zero of three water samples exceeded the aquatic life evaluation guideline for additive effects of chlorpyrifos and diazinon (Bailey et al., 1997). 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. 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. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of three water samples exceeded the evaluation guideline, and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107182, Organophosphate Pesticides	Region 3
Watsonville Slough

LOE ID:

173825

Pollutant:

Organophosphate Pesticides

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for the protection of aquatic life from the additive effects of the organophophate 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 (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 107182, Organophosphate Pesticides	Region 3
Watsonville Slough

LOE ID:

173458

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Joint acute toxicity of Diazinon and Chlorpyrifos to Ceriodaphnia dubia.

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107201	Region 3
Watsonville Slough

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

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

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 107201, Oryzalin	Region 3
Watsonville Slough

LOE ID:

173738

Pollutant:

Oryzalin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Oryzalin is the USEPA Aquatic Life Benchmark of 13 ug/L for a vascular plant (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-06-14 and 2011-06-14

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	107184	Region 3
Watsonville Slough

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

Regional Board Conclusion:	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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107184, Oxamyl (Vydate)	Region 3
Watsonville Slough

LOE ID:

173682

Pollutant:

Oxamyl (Vydate)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Oxamyl is the USEPA Aquatic Life Benchmark of 27 ug/L for an invertebrate (chronic).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107184, Oxamyl (Vydate)	Region 3
Watsonville Slough

LOE ID:

174012

Pollutant:

Oxamyl (Vydate)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Oxamyl is the USEPA Aquatic Life Benchmark of 27 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107206	Region 3
Watsonville Slough

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

Regional Board Conclusion:	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. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. One of the 10 samples exceed the evaluation guidelines for aquatic life protection (UC Davis Aquatic Life Criteria). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of the ten samples exceed the evaluation guidelines 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. 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 107206, Oxyfluorfen	Region 3
Watsonville Slough

LOE ID:

225385

Pollutant:

Oxyfluorfen

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceeded the water quality threshold for Oxyfluorfen.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Oxyfluorfen does not exceed 0.14 ug/L in the water column more than once every three years on average (Bower, et al. 2017).

Guideline Reference:

Water quality criteria report for Oxyfluorfen. Phase III: application of the pesticide water quality criteria methodology.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 107206, Oxyfluorfen	Region 3
Watsonville Slough

LOE ID:

174042

Pollutant:

Oxyfluorfen

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Water quality criteria report for Oxyfluorfen. Phase III: application of the pesticide water quality criteria methodology.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-06-14 and 2011-06-14

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	107219	Region 3
Watsonville Slough

Pollutant:	Paraquat
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 Clean Water Act (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. A total of one line of evidence is available in the administrative record to assess this pollutant. A total of zero of one sample exceeds the evaluation guideline for the warm freshwater habitat beneficial use. The readily available data and information are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 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. 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. A total of zero of one sample exceeds the evaluation guideline for the warm freshwater habitat beneficial use and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 107219, Paraquat	Region 3
Watsonville Slough

LOE ID:

176483

Pollutant:

Paraquat

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Paraquat is the USEPA Aquatic Life Benchmark of 0.396 ug/L for a nonvascular plant (acute) for Paraquat dichloride.

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107210	Region 3
Watsonville Slough

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

Regional Board Conclusion:	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. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the nine samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 107210, Pendimethalin	Region 3
Watsonville Slough

LOE ID:

225453

Pollutant:

Pendimethalin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Pendimethalin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Pendimethalin is the USEPA Aquatic Life Benchmark of 5.2 ug/L for a nonvascular plant (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107210, Pendimethalin	Region 3
Watsonville Slough

LOE ID:

176602

Pollutant:

Pendimethalin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Pendimethalin is the USEPA Aquatic Life Benchmark of 5.2 ug/L for a nonvascular plant (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-06-14 and 2011-06-14

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	107186	Region 3
Watsonville Slough

Pollutant:	Pentachlorophenol (PCP)
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107186, Pentachlorophenol (PCP)	Region 3
Watsonville Slough

LOE ID:

176493

Pollutant:

Pentachlorophenol (PCP)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The criterion continuous concentration to protect aquatic life in saline water is 7.9 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-04-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107186, Pentachlorophenol (PCP)	Region 3
Watsonville Slough

LOE ID:

176540

Pollutant:

Pentachlorophenol (PCP)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Human health risk associated with organism consumption is 8.2 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-04-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107186, Pentachlorophenol (PCP)	Region 3
Watsonville Slough

LOE ID:

176428

Pollutant:

Pentachlorophenol (PCP)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Pentachlorophenol criterion continuous concentration (expressed as a 4-day average) to protect aquatic life in freshwater is pH dependent. The criteria has a value of 15 ug/L when based on a default pH of 7.8. (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-04-27

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107222	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 at least one line of evidence is necessary to assess listing status, but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the section 303(d) List. Five lines of evidence are available in the administrative record to assess this pollutant. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of sixteen sediment samples and zero of the nine water samples exceed the evaluation guideline used to interpret the narrative water quality objective for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107222, Permethrin	Region 3
Watsonville Slough

LOE ID:

94107

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Permethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for permethrin is the median lethal concentration (LC50) of 8.9 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 8.9 ug/g is the geometric mean of LC50 values for permethrin from Amweg et al. (2005).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107222, Permethrin	Region 3
Watsonville Slough

LOE ID:

58963

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Permethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107222, Permethrin	Region 3
Watsonville Slough

LOE ID:

155328

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107222, Permethrin	Region 3
Watsonville Slough

LOE ID:

155463

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107222	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 at least one line of evidence is necessary to assess listing status, but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the section 303(d) List. Five lines of evidence are available in the administrative record to assess this pollutant. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of sixteen sediment samples and zero of the nine water samples exceed the evaluation guideline used to interpret the narrative water quality objective for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107222, Permethrin	Region 3
Watsonville Slough

LOE ID:

94185

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for PERMETHRIN.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the 4-day average concentration of permethrin does not exceed 0.002 ug/L and if the 1-h average concentration does not exceed 0.01 ug/L. Mixtures of permethrin and other pyrethroids should be considered in an additive manner. (Fojut et al. 2012)

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: ll. Pyrethroid insecticides. Reviews of Environmental Contamination and Toxicology 216:51-103.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA


DECISION ID	107188	Region 3
Watsonville Slough

Pollutant:	Phenol
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107188, Phenol	Region 3
Watsonville Slough

LOE ID:

179839

Pollutant:

Phenol

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Human health risk associated with organism consumption is 4,600,000 ug/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107211	Region 3
Watsonville Slough

Pollutant:	Phorate
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 section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of two water samples exceeded the USEPA aquatic life evaluation guideline. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported using table 3.1. 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. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero samples exceed the evaluation guidelines. 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107211, Phorate	Region 3
Watsonville Slough

LOE ID:

180290

Pollutant:

Phorate

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Phorate is the USEPA Aquatic Life Benchmark of 0.21 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107213	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. LOE 94186 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the ten samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107213, Phosmet	Region 3
Watsonville Slough

LOE ID:

180742

Pollutant:

Phosmet

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Phosmet is the USEPA Aquatic Life Benchmark of 0.8 ug/L for a invertebrate (acute).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107213, Phosmet	Region 3
Watsonville Slough

LOE ID:

225209

Pollutant:

Phosmet

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Phosmet.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Phosmet is the USEPA Aquatic Life Benchmark of 0.8 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107220	Region 3
Watsonville Slough

Pollutant:	Prodiamine
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 107220, Prodiamine	Region 3
Watsonville Slough

LOE ID:

180557

Pollutant:

Prodiamine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Prodiamine is the USEPA Aquatic Life Benchmark of 1.5 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-06-14 and 2011-06-14

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):


DECISION ID	129874	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. LOE 94187 has been removed from this decision and replaced with new LOEs that assess the data using the UC Davis Aquatic Life Criteria. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the nine samples exceed the evaluation guidelines for aquatic life protection (UC Davis Aquatic Life Criteria). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 129874, Prometryn	Region 3
Watsonville Slough

LOE ID:

225524

Pollutant:

Prometryn

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the water quality threshold for Prometryn.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

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 in the water column more than once every three years on average (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 (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	129880	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence are available in the administrative record to assess this pollutant. LOE 94189 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 129880, Propiconazole	Region 3
Watsonville Slough

LOE ID:

225551

Pollutant:

Propiconazole

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Propiconazole.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Propiconazole is the USEPA Aquatic Life Benchmark of 21 ug/L for a nonvascular plant (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107197	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the Section 303(d) List. Two lines of evidence are available in the administrative record to assess this pollutant. One of the four sediment samples exceed the evaluation guideline applied to protect for aquatic life beneficial uses. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1 of the Listing Policy. Therefore, the use support rating is set to 'insufficient information'. 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. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One of the four sediment samples exceed the evaluation guideline applied to protect for aquatic life beneficial uses 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107197, Pyrethroids	Region 3
Watsonville Slough

LOE ID:

155773

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for the protection of aquatic life from pyrethroids is one toxic unit. Individual pyrethroid concentrations in sediment were normalized to organic carbon content, divided by the respective LC50 and then summed. A sum over over one toxic unit is an exceedance of the evaluation guideline (Amweg et al. 2006).

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Guideline Reference:

Pyrethroid insecticides and sediment toxicity in urban creeks from California and Tennessee. Environmental Science and Technology, 40(5): 1700-1706

Guideline Reference:

Compilation of freshwater OC-normalized sediment toxicity data for pyrethroids

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2011-05-24 to 2011-05-24

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107197, Pyrethroids	Region 3
Watsonville Slough

LOE ID:

155695

Pollutant:

Pyrethroids

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Guideline Reference:

Partitioning, bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments. Environmental Toxicology and Chemistry 21:9-15

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Guideline Reference:

Pyrethroid insecticides and sediment toxicity in urban creeks from California and Tennessee. Environmental Science and Technology, 40(5): 1700-1706

Guideline Reference:

Compilation of freshwater OC-normalized sediment toxicity data for pyrethroids

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107190	Region 3
Watsonville Slough

Pollutant:	Selenium
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107190, Selenium	Region 3
Watsonville Slough

LOE ID:

180822

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 3 samples exceeded the water quality threshold for Selenium.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The criterion continuous concentration to protect aquatic life in freshwater is 0.005 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107190, Selenium	Region 3
Watsonville Slough

LOE ID:

181290

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

The criterion continuous concentration to protect aquatic life from dissolved selenium in saline water is 0.071 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107190, Selenium	Region 3
Watsonville Slough

LOE ID:

181396

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The criterion continuous concentration to protect aquatic life from dissolved selenium in saline water is 0.071 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107190, Selenium	Region 3
Watsonville Slough

LOE ID:

181262

Pollutant:

Selenium

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The criterion continuous concentration to protect aquatic life in freshwater is 0.005 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107191	Region 3
Watsonville Slough

Pollutant:	Silver
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:	This decision was made by SWRCB staff.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should 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 107191, Silver	Region 3
Watsonville Slough

LOE ID:

181808

Pollutant:

Silver

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 SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 2 samples exceeded the water quality threshold for Silver.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion maximum concentrations to protect aquatic life in freshwater. The criterion in freshwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107191, Silver	Region 3
Watsonville Slough

LOE ID:

181805

Pollutant:

Silver

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

California Toxics Rule (CTR) lists criterion maximum concentrations to protect aquatic life in saltwater. The criterion in saltwater is hardness dependent for each sample and varies based on the ambient hardness during sampling. Section (b)(1) in CTR contains the hardness dependent formula for the metals criterion.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	107192	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. LOE 94191 has been removed from this decision and replaced with new LOEs that assess the data using the USEPA aquatic life benchmarks. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the nine samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107192, Simazine	Region 3
Watsonville Slough

LOE ID:

225583

Pollutant:

Simazine

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Simazine.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

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

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107192, Simazine	Region 3
Watsonville Slough

LOE ID:

181839

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

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

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2014-02-28

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	107224	Region 3
Watsonville Slough

Pollutant:	Thiamethoxam
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 107224, Thiamethoxam	Region 3
Watsonville Slough

LOE ID:

156493

Pollutant:

Thiamethoxam

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Thiamethoxam is the USEPA Aquatic Life Benchmark of 0.74 ug/L for an invertebrate (chronic).

Guideline Reference:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):


DECISION ID	129881	Region 3
Watsonville Slough

Pollutant:	Thiobencarb
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. One line of evidence is available in the administrative record to assess this pollutant. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the eight samples exceed the evaluation guidelines for aquatic life protection (USEPA benchmark). These sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating.

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 129881, Thiobencarb	Region 3
Watsonville Slough

LOE ID:

225613

Pollutant:

Thiobencarb

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 8 samples exceeded the water quality threshold for Thiobencarb.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Thiobencarb is the USEPA Aquatic Life Benchmark of 1 ug/L for a invertebrate (acute).

Guideline Reference:

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):


DECISION ID	107194	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. LOE 94193 has been removed from this decision and replaced with new LOEs that assess the data using the UC Davis Aquatic Life Criteria. Where the fraction is not recorded, staff assumed that the fraction was total and summed sample and exceedance counts for the purpose of making this decision. Zero of the 11 samples exceed the evaluation guidelines for aquatic life protection (UC Davis Aquatic Life Criteria). This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 107194, Trifluralin	Region 3
Watsonville Slough

LOE ID:

156276

Pollutant:

Trifluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

UC Davis Aquatic Life Criteria: Aquatic life should not be affected unacceptably if the four-day average concentration of Trifluralin does not exceed 0.33 ug/L in the water column more than once every three years on average (Bower, et al. 2017).

Guideline Reference:

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

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-06-14 and 2011-06-14

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 107194, Trifluralin	Region 3
Watsonville Slough

LOE ID:

156297

Pollutant:

Trifluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded the water quality threshold for Trifluralin. 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:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

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

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Data for this waterbody was collected over the date range 2014-02-28 to 2017-12-13

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107194, Trifluralin	Region 3
Watsonville Slough

LOE ID:

225538

Pollutant:

Trifluralin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceeded the water quality threshold for Trifluralin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

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

Spatial Representation:

The samples were collected at 1 monitoring site (305WAB)

Temporal Representation:

The samples were collected between the dates of 2008-01-07 and 2009-10-28

Environmental Conditions:

QAPP Information:

QAPP not required

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	107196	Region 3
Watsonville Slough

Pollutant:	Zinc
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 Clean Water Act (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. A total of four lines of evidence are available in the administrative record to assess this pollutant. A total of zero of 27 samples exceed the water quality objective for the estuarine habitat beneficial use and zero of 27 samples exceed the water quality objective for the warm freshwater habitat beneficial use. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed 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. A total of zero of 27 samples exceed the water quality objective for the estuarine habitat beneficial use and zero of 27 samples exceed the water quality objective for the warm freshwater habitat beneficial use. This does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:

Line of Evidence (LOE) for Decision ID 107196, Zinc	Region 3
Watsonville Slough

LOE ID:

156818

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107196, Zinc	Region 3
Watsonville Slough

LOE ID:

156593

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107196, Zinc	Region 3
Watsonville Slough

LOE ID:

156664

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 24 samples exceeded the water quality threshold for Zinc.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2011-01-12 and 2017-12-05

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107196, Zinc	Region 3
Watsonville Slough

LOE ID:

156400

Pollutant:

Zinc

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2011-01-12 and 2017-12-05

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	107187	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Forty-seven lines of evidence is available in the administrative record to assess this pollutant. One hundred of the 1181 samples exceed the maximum pH water quality objective for Contact and Non-contact Recreation beneficial uses. One hundred twenty-three of the 1230 samples exceed the maximum pH water quality objective for Warm Freshwater Habitat. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. One hundred of the 1181 samples exceed the maximum pH water quality objective for Contact and Non-contact Recreation beneficial uses, 123 of the 1230 samples exceed the maximum pH water quality objective for Warm Freshwater Habitat and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

State Board Decision Recommendation:	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 107187, pH	Region 3
Watsonville Slough

LOE ID:

58969

Pollutant:

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:

Thirteen of 34 samples exceeded the objective.

Data Reference:

City of Watsonville Restoration Project Water Quality Data, Aug. 2004-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall not be depressed below 7.0, nor raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from Site 2. Site 1 data was omitted because it has effluent data only.

Temporal Representation:

Samples were collected once in 2004 and approximately once every other month between January 2005 to June 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

178067

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 57 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan, Central Coast Basin objective for water contact recreation (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 6.5 nor raised above 8.3.

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2010-05-25 and 2018-12-19

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

48910

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Water Board Staff assessed public submissions data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 21 samples exceed the criterion for pH.

Data Reference:

Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSAxxx - Watsonville Slough upstream Harkins Slough]

Temporal Representation:

Data was collected over the time period 2/14/2007-6/29/2010.

Environmental Conditions:

Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

58968

Pollutant:

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:

Four of 15 samples exceeded the objective.

Data Reference:

City of Watsonville Long Term Management Strategy Data, May 2009-Jul. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall not be depressed below 7.0, nor raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Samples were collected from Watsonville Slough at Ohlone Parkway bridge.

Temporal Representation:

Samples were collected approximately once a month from May 2009 to July 2010.

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

48188

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 3 - Central Coast Region staff assessed R3 public submissions data for Watsonville Slough to determine beneficial use support and results are as follows: 2 of 9 samples exceed the criterion for pH.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input]

Temporal Representation:

Data was collected over the time period 1/7/2008 5:00:00 PM-10/28/2009 10:31:30 AM.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

19149

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/13/2004-11/12/2004.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

18914

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/17/2003-5/6/2006. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.

Environmental Conditions:

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

QAPP Information:

State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

17613

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

908

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A

Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 10/4/2000-2/6/2007.

Environmental Conditions:

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

QAPP Information:

Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

13852

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 6 monitoring sites [ Shell Rd at pump station, Pajaro Dunes Colony near confluence with Pajaro R, Lee Rd, Errington Rd, San Andreas Rd, Harkins Slough Rd]

Temporal Representation:

Data was collected over the time period 2/18/2003-3/1/2004.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

13725

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data

Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

48189

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Region 3 - Central Coast Region staff assessed R3 public submissions data for Watsonville Slough to determine beneficial use support and results are as follows: 3 of 9 samples exceed the criterion for pH.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall not be depressed below 7.0 or raised above 8.5 (Basin Plan).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input]

Temporal Representation:

Data was collected over the time period 1/7/2008 5:00:00 PM-10/28/2009 10:31:30 AM.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

13853

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 2/18/2003-3/1/2004.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

13726

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data

Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

48911

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Water Board Staff assessed public submissions data for Watsonville Slough to determine beneficial use support and results are as follows: 4 of 21 samples exceed the criterion for pH.

Data Reference:

Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall not be depressed below 7.0 or raised above 8.5 (Basin Plan).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSAxxx - Watsonville Slough upstream Harkins Slough]

Temporal Representation:

Data was collected over the time period 2/14/2007-6/29/2010.

Environmental Conditions:

Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

17614

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

908

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A

Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 10/4/2000-2/6/2007.

Environmental Conditions:

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

QAPP Information:

Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

19150

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/13/2004-11/12/2004.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

11109

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for Watsonville Slough to determine beneficial use support and results are as follows: 2 of 12 samples exceed the criterion for pH.

Data Reference:

Final Data File used for assessment: CCAMP Water Quality Data_file1

Final Data File used for assessment: CCAMP Water Quality Data_file2

Final Data File used for assessment: CCAMP Water Quality Data_file3

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Data was collected over the time period 1/24/2005-3/16/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

13851

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: pH value shall neither be depressed below 6.5 nor raised above 8.3.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 2/18/2003-3/1/2004.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

18915

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan, Central Coast Basin, General Objective, Chapter III, Section II.A.2 General Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries states the following: For waters not mentioned by a specific beneficial use, the pH value shall not be depressed below 7.0 or raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/17/2003-5/6/2006. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.

Environmental Conditions:

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

QAPP Information:

State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

11107

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: CCAMP Water Quality Data_file1

Final Data File used for assessment: CCAMP Water Quality Data_file2

Final Data File used for assessment: CCAMP Water Quality Data_file3

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Data was collected over the time period 1/24/2005-3/16/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

19148

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/13/2004-11/12/2004.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

18897

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Monterey Bay National Marine Sanctuary Volunteer Monitoring Network Data. 2003-2006

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/17/2003-5/6/2006. Coastal Watershed Council Snapshot Day Monitoring is conducted annually.

Environmental Conditions:

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

QAPP Information:

State Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

48187

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input]

Temporal Representation:

Data was collected over the time period 1/7/2008 5:00:00 PM-10/28/2009 10:31:30 AM.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

48909

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Water Board Staff assessed public submissions data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 21 samples exceed the criterion for pH.

Data Reference:

Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The pH value shall neither be depressed below 6.5 nor raised above 8.3 (Basin Plan).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSAxxx - Watsonville Slough upstream Harkins Slough]

Temporal Representation:

Data was collected over the time period 2/14/2007-6/29/2010.

Environmental Conditions:

Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

13692

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data

Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

17612

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

908

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: Marc Los Huertos Water Quality Data, file A

Final Data File used for assessment: Marc Los Huertos Water Quality Data, file B

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 10/4/2000-2/6/2007.

Environmental Conditions:

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

QAPP Information:

Regional Board approved QAPP. Multiple errors were identified in data and were flagged or fixed by RB staff (in communication with Project staff) prior to assessment of data.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179118

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 6.5 nor raised above 8.3.

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-21)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

178236

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-22)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179115

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and results are as follows: 2 of 19 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2011-01-12 and 2017-11-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179760

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

The Water Quality Control Plan, Central Coast Basin objective for warm fresh water habitat (Section 3.3.2 Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries) states that the pH value shall neither be depressed below 7.0 nor raised above 8.5.

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-23)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179310

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2011-01-12 and 2017-11-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179623

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-22)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179704

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-23)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179595

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-21)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179886

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2010-05-25 and 2018-12-19

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179271

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed EPA CRAM Validation data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305MANDWx)

Temporal Representation:

The samples were collected between the dates of 2014-08-05 and 2014-08-05

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Support for L2 Committee Priority Tool Development: Validation of Three CRAM Modules Task 3: Validation of the Depressional Wetland CRAM Module

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

177953

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed EPA CRAM Validation data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305MANDWx)

Temporal Representation:

The samples were collected between the dates of 2014-08-05 and 2014-08-05

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Support for L2 Committee Priority Tool Development: Validation of Three CRAM Modules Task 3: Validation of the Depressional Wetland CRAM Module

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

177583

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-23)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

180044

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-22)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

178456

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-BEACH-21)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179738

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-WATSO-21)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179767

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2011-01-12 and 2017-11-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179778

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-BEACH-21)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179955

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and results are as follows: 14 of 57 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2010-05-25 and 2018-12-19

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

179622

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed EPA CRAM Validation data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305MANDWx)

Temporal Representation:

The samples were collected between the dates of 2014-08-05 and 2014-08-05

Environmental Conditions:

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Support for L2 Committee Priority Tool Development: Validation of Three CRAM Modules Task 3: Validation of the Depressional Wetland CRAM Module

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

177269

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed MBNMS Snapshot Day data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 1 samples exceeded the water quality threshold for pH.

Data Reference:

Field, Habitat, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305-BEACH-21)

Temporal Representation:

The samples were collected between the dates of 2015-05-02 and 2015-05-02

Environmental Conditions:

QAPP Information:

Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP).

QAPP Information Reference(s):

California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP)

Line of Evidence (LOE) for Decision ID 107187, pH	Region 3
Watsonville Slough

LOE ID:

11108

Pollutant:

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Non-Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: CCAMP Water Quality Data_file1

Final Data File used for assessment: CCAMP Water Quality Data_file2

Final Data File used for assessment: CCAMP Water Quality Data_file3

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Data was collected over the time period 1/24/2005-3/16/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):


DECISION ID	107221	Region 3
Watsonville Slough

Pollutant:	Aluminum
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	No Source Analysis Available
Expected TMDL Completion Date:	2035
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under section 3.1 of the Listing Policy. One line of evidence is available in the administrative record to assess this pollutant. Three of three water samples exceed the evaluation guideline applied to protect aquatic life beneficial use. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Three of three water samples exceed the evaluation guideline applied to protect aquatic life beneficial use 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:

Line of Evidence (LOE) for Decision ID 107221, Aluminum	Region 3
Watsonville Slough

LOE ID:

233026

Pollutant:

Aluminum

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 SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and results are as follows: 3 of 3 samples exceeded the water quality threshold for Aluminum.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The National Recommended Water Quality Criteria for the protection of aquatic life from aluminum, expressed in terms of total recoverable metal in the water column, is the chronic continuous concentration (4-day average) of 87 ug/L.

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	107162	Region 3
Watsonville Slough

Pollutant:	Chlorpyrifos
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2018)
Revision Status	Revised
Sources:	No Source Analysis Available
Expected TMDL Completion Date:	2035
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Eleven lines of evidence are available in the administrative record to assess this pollutant. For lines of evidence where the fraction is "none' or "not recorded" staff assumed that the fraction is "total", based on the analytical method, and the sample and exceedance counts are summed for both fractions for the purpose of making this decision. Two of 12 water samples exceed the evaluation guideline (Siepmann and Finlayson 2000) for the estuarine beneficial use and this sample size is sufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating of "not supporting". One of 19 water samples exceed the aquatic life evaluation guideline (Siepmann and Finlayson 2000, with minor corrections to significant figures as described in Beaulaurier et al., 2005). This sample size is sufficient to determinet he applicable beneficial use support rating of "fully supporting". Zero of 12 sediment samples exceed the aquatic life evaluation guideline (Amweg and Weston, 2007) and this sample size is insufficient to determine the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported using table 3.1. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the CWA section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of 12 water samples exceeded the evaluation guideline for the estuarine beneficial use 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 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

151845

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for chlorpyrifos is the median lethal concentration (LC50) of 1.77 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Amweg and Weston, 2007).

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Data were collected from 1 station(s). Station Code(s): 305WSA.

Temporal Representation:

Data for this waterbody were collected over the date range 2010-05-25 to 2018-04-24

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

94036

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Chlorpyrifos.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for chlorpyrifos is the median lethal concentration (LC50) of 1.77 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Amweg and Weston, 2007).

Guideline Reference:

Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: I. piperonyl butoxide addition. Environ. Toxicol. Chem. 26:2389-2396.

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

94166

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceed the criterion for CHLORPYRIFOS.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The saltwater criterion continuous concentration to protect aquatic organisms is 0.009 ug/L (Siepmann and Finlayson 2000).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

16330

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: SWAMP Toxicity Data 2001-06

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Objective/Criterion Reference:

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

Evaluation Guideline:

One hour average maximum concentration 0.025 ug/L as stated in Sipmann and Finlayson (2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA001 - Watsonville Slough above pump station at San Andreas]

Temporal Representation:

Data was collected over the time period 1/12/2006-5/30/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

94167

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceed the criterion for CHLORPYRIFOS.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

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:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

16007

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: SWAMP Toxicity Data 2001-06

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Objective/Criterion Reference:

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

Evaluation Guideline:

One hour average maximum concentration 0.025 ug/L as stated in Sipmann and Finlayson (2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA001 - Watsonville Slough above pump station at San Andreas]

Temporal Representation:

Data was collected on a single day 5/3/2006. SWAMP toxicity monitoring includes both water samples (collected in both winter and summer) and sediment samples (collected in spring).

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

18601

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Final Data File used for assessment: DHS Sediment Chemistry Data, File 1 (feb06)

Final Data File used for assessment: DHS Sediment Chemistry Data, File 2 (sed06)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Objective/Criterion Reference:

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

Evaluation Guideline:

One hour average maximum concentration 0.025 ug/L as stated in Sipmann and Finlayson (2000).

Guideline Reference:

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

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA_DHS - Watsonville Slough]

Temporal Representation:

Data was collected over the time period 12/13/1994-1/27/1995.

Environmental Conditions:

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

QAPP Information:

No QAPP was provided for this data set.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

161511

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The saltwater criterion continuous concentration to protect aquatic organisms is 0.009 ug/L (Siepmann and Finlayson 2000).

Guideline Reference:

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

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

161553

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

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 (305WASSHE)

Temporal Representation:

The samples were collected between the dates of 2011-04-26 and 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

161343

Pollutant:

Chlorpyrifos

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed Surface Water Monitoring Project data for Watsonville Slough to determine beneficial use support and the results are as follows: 1 of the 1 samples exceeded the water quality threshold for Chlorpyrifos. Although a total of 3 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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The saltwater criterion continuous concentration to protect aquatic organisms is 0.009 ug/L (Siepmann and Finlayson 2000).

Guideline Reference:

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

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-04-26 to 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.

Line of Evidence (LOE) for Decision ID 107162, Chlorpyrifos	Region 3
Watsonville Slough

LOE ID:

161551

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:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	107163	Region 3
Watsonville Slough

Pollutant:	Copper
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	No Source Analysis Available
Expected TMDL Completion Date:	2035
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the Clean Water Act (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. A total of four lines of evidence are available in the administrative record to assess this pollutant. A total of six of 13 samples exceed the water quality objective for the estuarine habitat beneficial use and zero of 14 samples exceed the water quality objective for the warm freshwater habitat beneficial use. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed 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. A total of six of 13 samples exceed the water quality objective for the estuarine habitat beneficial use and zero of 14 samples exceed the water quality objective for the warm freshwater habitat beneficial use. 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:

Line of Evidence (LOE) for Decision ID 107163, Copper	Region 3
Watsonville Slough

LOE ID:

162514

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107163, Copper	Region 3
Watsonville Slough

LOE ID:

161984

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107163, Copper	Region 3
Watsonville Slough

LOE ID:

161985

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and the results are as follows: 0 of the 12 samples exceeded the water quality threshold for Copper. Although a total of 24 samples were collected, 12 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-01-12 to 2017-12-05

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107163, Copper	Region 3
Watsonville Slough

LOE ID:

162578

Pollutant:

Copper

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed SWAMP RWB3 CCAMP Pajaro and Santa Cruz Area data for Watsonville Slough to determine beneficial use support and the results are as follows: 5 of the 11 samples exceeded the water quality threshold for Copper. Although a total of 24 samples were collected, 13 of these samples were not included in the assessment because the laboratory data reporting limit(s) was above the water quality threshold and therefore the results could not be quantified with the level of certainty required by the Listing Policy Section 6.1.5.5.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-01-12 to 2017-12-05

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program


DECISION ID	107198	Region 3
Watsonville Slough

Pollutant:	Imidacloprid
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	No Source Analysis Available
Expected TMDL Completion Date:	2027
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. Three of the four water samples exceed the evaluation guideline applied to protect aquatic life beneficial uses. This exceeds the allowable frequency listed in Table 3.1 of the Listing Policy. 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. Three of the four water samples exceed the evaluation guideline. 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:

Line of Evidence (LOE) for Decision ID 107198, Imidacloprid	Region 3
Watsonville Slough

LOE ID:

167177

Pollutant:

Imidacloprid

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Aquatic life should not be affected unacceptably if the 4-day average concentration of Imidacloprid does not exceed 0.016 ug/L. (UC Davis Water Quality Criteria)

Guideline Reference:

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

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-12-13 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107198, Imidacloprid	Region 3
Watsonville Slough

LOE ID:

167157

Pollutant:

Imidacloprid

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

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 Surface Water Monitoring Project data for Watsonville Slough to determine beneficial use support and the results are as follows: 2 of the 2 samples exceeded the water quality threshold for Imidacloprid. Although a total of 3 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:

Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. (Water Quality Control Plan, Central Coast Basin, General Objective Chapter III, Section II.A.2 Objectives for all Inland Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Aquatic life should not be affected unacceptably if the 4-day average concentration of Imidacloprid does not exceed 0.016 ug/L. (UC Davis Water Quality Criteria)

Guideline Reference:

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

Spatial Representation:

The samples were collected at 1 monitoring site (305WASSHE).

Temporal Representation:

Data for this waterbody was collected over the date range 2011-04-26 to 2011-07-18

Environmental Conditions:

QAPP Information:

Data is exempt from QAPP requirement

QAPP Information Reference(s):

This is a placeholder reference for data that was collected after QAPP requirements were developed, but exempt from the requirements.


DECISION ID	107178	Region 3
Watsonville Slough

Pollutant:	Nickel
Final Listing Decision:	List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	New Decision
Revision Status	Revised
Sources:	No Source Analysis Available
Expected TMDL Completion Date:	2035
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the Clean Water Act (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. A total of seven lines of evidence are available in the administrative record to assess this pollutant. A total of zero of three samples exceed the dissolved fraction water quality objective and zero of six samples exceed the total fraction water quality objective for the commercial or recreational collection of fish, shellfish, or organisms beneficial use, six of six samples exceed the water quality objective for the estuarine habitat beneficial use and zero of six samples exceed the water quality objective for the warm freshwater habitat beneficial use. After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be placed 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. A total of zero of three samples exceed the dissolved fraction water quality objective and zero of six samples exceed the total fraction water quality objective for the commercial or recreational collection of fish, shellfish, or organisms beneficial use, six of six samples exceed the water quality objective for the estuarine habitat beneficial use and zero of six samples exceed the water quality objective for the warm freshwater habitat beneficial use. 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:

Line of Evidence (LOE) for Decision ID 107178, Nickel	Region 3
Watsonville Slough

LOE ID:

170639

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Human health risk associated with organism consumption is 4.6 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107178, Nickel	Region 3
Watsonville Slough

LOE ID:

170559

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107178, Nickel	Region 3
Watsonville Slough

LOE ID:

170854

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107178, Nickel	Region 3
Watsonville Slough

LOE ID:

170984

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Total

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Human health risk associated with organism consumption is 4.6 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107178, Nickel	Region 3
Watsonville Slough

LOE ID:

170707

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Water Board staff assessed RWB3 Cooperative Monitoring Program data for Watsonville Slough to determine beneficial use support and results are as follows: 3 of 3 samples exceeded the water quality threshold for Nickel.

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

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 (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107178, Nickel	Region 3
Watsonville Slough

LOE ID:

170675

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Estuarine Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2017-03-02 and 2017-09-07

Environmental Conditions:

QAPP Information:

SWAMP 2008

QAPP Information Reference(s):

Quality Assurance Program Plans, Quality Assurance Project Plans, and Standard Operating Procedures for the SWAMP program

Line of Evidence (LOE) for Decision ID 107178, Nickel	Region 3
Watsonville Slough

LOE ID:

170610

Pollutant:

Nickel

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Dissolved

Beneficial Use:

Commercial or recreational collection of fish, shellfish, or organisms

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Data Reference:

Field, Habitat, Sediment, Toxicity, Water data for the 2020/2022 integrated report in Region 3.

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Human health risk associated with organism consumption is 4.6 mg/L (California Toxics Rule, 2000).

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

The samples were collected at 1 monitoring site (305WSA)

Temporal Representation:

The samples were collected between the dates of 2014-02-28 and 2018-03-02

Environmental Conditions:

QAPP Information:

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6.

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6


DECISION ID	68877	Region 3
Watsonville Slough

Pollutant:	Pesticides
Final Listing Decision:	Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (TMDL required list)(2016)
Revision Status	Original
Reason for Delisting:	Change from general pollutant to specific pollutant listing (e.g. metals to copper)
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This decision for pesticides was made prior to 2006 and the supporting data and other information are not held in an assessment database. The historic administrative record does not include specific data for this decision. This decision for the general category of 'Pesticides' is being replaced by individual decisions for each of the pesticides for which there are data. This water segment is being assessed for a full suite of currently applied pesticides such as OP and pyrethroid pesticides. Those individual decisions replace this generic decision for pesticides.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because this decision for the general category of 'Pesticides' is being replaced by individual decisions for each of the pesticides for which there are data.

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 68877, Pesticides	Region 3
Watsonville Slough

LOE ID:

4021

Pollutant:

Pesticides

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

Not Recorded

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

Placeholder reference pre-2006 303(d)

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Unspecified

Objective/Criterion Reference:

Placeholder reference pre-2006 303(d)

Evaluation Guideline:

Unspecified

Guideline Reference:

Placeholder reference pre-2006 303(d)

Spatial Representation:

Unspecified

Temporal Representation:

Unspecified

Environmental Conditions:

Unspecified

QAPP Information:

Unspecified

QAPP Information Reference(s):


DECISION ID	84058	Region 3
Watsonville Slough

Pollutant:	Pathogens
Final Listing Decision:	Delist from 303(d) list (being addressed by USEPA approved TMDL)
Last Listing Cycle's Final Listing Decision:	Delist from 303(d) list (being addressed by USEPA approved TMDL)(2016)
Revision Status	Original
Reason for Delisting:	Change from general pollutant to specific pollutant listing (e.g. metals to copper)
TMDL Name:	Watsonville Slough Pathogen
TMDL Project Code:	35
Date TMDL Approved by USEPA:	07/19/2007
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This decision for the general category of 'Pathogens' is being replaced by individual decisions for each of the Indicator Bacteria for which there are data, such as E. coli and fecal coliform. Those individual decisions replace this generic decision. This decision for 'Pathogens' was made prior to 2006 and the supporting data and other information are not held in an assessment database. The historic administrative record does not include specific data for this decision. Furthermore, newer data for individual pollutants are available and will be assessed under individual decisions. Those decisions will replace this decision for the generic pollutant category 'Pathogens'. This conclusion is based on the staff findings that: 1. The data used for the original decision are not available and therefore do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used for the original decision are not available and therefore do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. No data is available to assess the status of this water body for this generic pollutant and newer data for individual pollutants under this general category are available and are assessed in separate decisions. 4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available for this general category

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because this decision for the general category of 'Pathogens' is being replaced by individual decisions for each of the fecal indicator bacteria for which there are data.

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 84058, Pathogens	Region 3
Watsonville Slough

LOE ID:

1857

Pollutant:

Pathogens

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Water Contact Recreation

Number of Samples:

Number of Exceedances:

Data and Information Type:

PATHOGEN MONITORING

Data Used to Assess Water Quality:

Unspecified--This LOE is a placeholder to support a 303(d) listing decision made prior to 2006.

Data Reference:

Final Data File used for assessment: CCAMP Water Quality Data_file1

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

QA Info Missing

QAPP Information Reference(s):


DECISION ID	107161	Region 3
Watsonville Slough

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

Regional Board Conclusion:	No new data were assessed for the 2020 listing cycle. This pollutant is being considered for placement on the CWA section 303(d) List under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Three lines of evidence are available in the administrative record to assess this pollutant. Two of the 37 samples exceed the evaluation guideline (North Carolina Administrative code, Title 15A) used to interpret the narrative water quality objective for bio-stimulation risk and aquatic life beneficial uses. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Two of the 37 samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 107161, Chlorophyll-a	Region 3
Watsonville Slough

LOE ID:

9405

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Regional Board Staff assessed CCAMP Pajaro (Pajaro) data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 11 samples exceed the criterion for Chlorophyll a.

Data Reference:

Final Data File used for assessment: CCAMP Water Quality Data_file2

Final Data File used for assessment: CCAMP Water Quality Data_file3

SWAMP Data:

SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Objective/Criterion Reference:

Water quality standards table

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Evaluation Guideline:

North Carolina Administrative code (NCAC), Title 15A - Environmental and Natural Resources, Subchapter 2B-Surface water and wetland standards, Rule 0211-Fresh surface water quality standards for class C waters (Class C is defined as freshwaters protected for secondary recreation, fishing, aquatic life including propagation and survival, and wildlife). Section 3(a) of Rule 0211 applies to all fresh surface waters and states that chlorophyll a is not to exceed 40 ug/L.

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Data was collected over the time period 1/24/2005-3/16/2006. Pajaro watershed is one of five annual rotation areas that are monitored for conventional pollutants by CCAMP staff monthly for one year.

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 107161, Chlorophyll-a	Region 3
Watsonville Slough

LOE ID:

48893

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Water Board Staff assessed public submissions data for Watsonville Slough to determine beneficial use support and results are as follows: 2 of 21 samples exceed the criterion for Chlorophyll a.

Data Reference:

Data from Region 3 Conditional Waiver Cooperative Monitoring Program, Jan. 2007-Jun. 2010

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Guideline Reference:

Water quality standards table

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSAxxx - Watsonville Slough upstream Harkins Slough]

Temporal Representation:

Data was collected over the time period 2/14/2007-6/29/2010.

Environmental Conditions:

Central Coast Water Board Staff are not aware of any special conditions that might affect interpretation of the data.

QAPP Information:

QAPP Information Reference(s):

Quality Assurance Project Plan for Monitoring for the Region 3 Conditional Ag Waiver Cooperative Monitoring Program, Revision 6

Line of Evidence (LOE) for Decision ID 107161, Chlorophyll-a	Region 3
Watsonville Slough

LOE ID:

13689

Pollutant:

Chlorophyll-a

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Aquatic Life Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

Central Coast Regional Board Staff assessed CCWQP Northern Area Ag-Waiver Monitoring (R3_CMPNorth) data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 5 samples exceed the criterion for Chlorophyll a.

Data Reference:

Final Data File used for assessment: Central Coast Water Quality Preservation Inc toxicity data

Final Data File used for assessment: Central Coast Water Quality Preservation Inc water quality data

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan (Basin Plan) - Central Coast Region (Region 3)

Objective/Criterion Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Objective/Criterion Reference:

Water quality standards table

Evaluation Guideline:

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Guideline Reference:

North Carolina standards, criteria, or toxic concentrations. Adopted per title 15A North Carolina Administrative Code subchapter 2B - Surface water and wetland standards

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WSA-Watsonville Slough at San Andreas Road]

Temporal Representation:

Environmental Conditions:

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

QAPP Information:

QAPP Information Reference(s):


DECISION ID	87530	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under section 3.6 of the Listing Policy. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the Section 303(d) list. One line of evidence is available in the administrative record to assess this pollutant. Zero of the twelve samples exceed the evaluation guideline used to interpret the narrative water quality objective for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) List in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the twelve samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

Line of Evidence (LOE) for Decision ID 87530, Fipronil	Region 3
Watsonville Slough

LOE ID:

58918

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Fipronil.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for fipronil is the median lethal concentration (LC50) of 0.13 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al. 2008).

Guideline Reference:

Effect of sediment-associated pyrethroids, fipronil, and metabolites on Chironomus tentans growth rate, body mass, condition index, immobilization, and survival. Environ. Toxicol. Chem. 27(12):2582-2590.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 87530, Fipronil	Region 3
Watsonville Slough

LOE ID:

94043

Pollutant:

Fipronil

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Fipronil.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for fipronil is the median lethal concentration (LC50) of 0.13 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al. 2008).

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	88038	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 of the Listing Policy, a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the Section 303(d) list. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the twelve sediment samples exceed the evaluation guideline for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the twelve samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

Line of Evidence (LOE) for Decision ID 88038, Fipronil Sulfide	Region 3
Watsonville Slough

LOE ID:

58919

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Fipronil sulfide.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for fipronil sulfide is the median lethal concentration (LC50) of 0.16 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al. 2008).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 88038, Fipronil Sulfide	Region 3
Watsonville Slough

LOE ID:

94044

Pollutant:

Fipronil Sulfide

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Fipronil sulfide.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for fipronil sulfide is the median lethal concentration (LC50) of 0.16 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al. 2008).

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	88039	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 of the Listing Policy, a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment. The pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the Section 303(d) list. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the twelve sediment samples exceed the evaluation guideline for aquatic life protection. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the twelve samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

Line of Evidence (LOE) for Decision ID 88039, Fipronil Sulfone	Region 3
Watsonville Slough

LOE ID:

58931

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Fipronil sulfone.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for fipronil sulfone is the median lethal concentration (LC50) of 0.12 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al. 2008).

Guideline Reference:

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 88039, Fipronil Sulfone	Region 3
Watsonville Slough

LOE ID:

94045

Pollutant:

Fipronil Sulfone

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Fipronil sulfone.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for fipronil sulfone is the median lethal concentration (LC50) of 0.12 ug/g and is normalized by the percentage of organic carbon in the sediment sample (Maul et al. 2008).

Guideline Reference:

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	88148	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Under section 3.6 at least two lines of evidence are necessary to assess listing status for pollutants in sediment and the pollutant concentration must be associated with toxicity to result in addition of the pollutant to the Section 303(d) list. Three lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine water samples exceed the evaluation guideline for aquatic life uses. Zero of the twelve sediment samples exceed the evaluation guideline for aquatic life uses. This sample sizes are insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the CWA section 303(d) List. This conclusion is based on the staff findings that: 1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy. 3. Zero of the nine water samples exceed the evaluation guideline for aquatic life uses and zero of the twelve sediment samples exceed the evaluation guideline for aquatic life uses. These do not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

Regional Board Decision Recommendation:	After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 88148, Methyl Parathion	Region 3
Watsonville Slough

LOE ID:

94046

Pollutant:

Methyl Parathion

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for methyl parathion.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for methyl parathion is the median lethal concentration (LC50) of 6 ug/g and is normalized by the percentage of organic carbon in the sediment sample. The LC50 6 ug/g is the geometric mean of LC50 values for methyl parathion from Ding et al. (2011).

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 88148, Methyl Parathion	Region 3
Watsonville Slough

LOE ID:

94184

Pollutant:

Methyl Parathion

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Parathion, methyl.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The California Department of Fish and Game instantaneous criteria for Methyl Parathion is 0.08 ug/L.

Guideline Reference:

Hazard Assessment of the Insecticide Methyl Parathion to Aquatic Organisms in the Sacramento River System

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 88148, Methyl Parathion	Region 3
Watsonville Slough

LOE ID:

58949

Pollutant:

Methyl Parathion

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Methyl parathion.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Toxicity of Sediment-Associated Pesticides to Chironomus dilutus and Hyalella azteca. Arch. Environ. Contam. Toxicol. 61:83¿92.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	85277	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under sections 3.1 and 3.6 of the Listing Policy. Under section 3.1 at least one line of evidence is necessary to assess listing status, but under section 3.6 at least two lines of evidence are necessary to assess listing status and the pollutant concentration in sediment must be associated with toxicity to result in addition of the pollutant to the section 303(d) List. Three lines of evidence are available in the administrative record to assess this pollutant. Zero of the nine water samples exceed the evaluation guideline used to interpret the narrative water quality objective for aquatic life protection. Zero of the twelve sediment samples exceeded the aquatic life evaluation guideline. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. None of the samples exceed the evaluation guideline and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.

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

Line of Evidence (LOE) for Decision ID 85277, Permethrin	Region 3
Watsonville Slough

LOE ID:

58963

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

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 USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 3 samples exceed the criterion for Permethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 7/2/2008-10/28/2009.

Environmental Conditions:

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

QAPP Information:

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.

Line of Evidence (LOE) for Decision ID 85277, Permethrin	Region 3
Watsonville Slough

LOE ID:

94185

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for PERMETHRIN.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Aquatic life water quality criteria derived via the UC Davis method: ll. Pyrethroid insecticides. Reviews of Environmental Contamination and Toxicology 216:51-103.

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Line of Evidence (LOE) for Decision ID 85277, Permethrin	Region 3
Watsonville Slough

LOE ID:

94107

Pollutant:

Permethrin

LOE Subgroup:

Pollutant-Sediment

Matrix:

Sediment

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Permethrin.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

Guideline Reference:

Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA. Environmental Toxicology and Chemistry, 24:966-972, with erratum 24:No. 5

Spatial Representation:

Temporal Representation:

Data was collected over the time period 5/29/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):

Quality Assurance Project Plan from UC Davis Marine Pollution Studies Laboratory.


DECISION ID	87554	Region 3
Watsonville Slough

Pollutant:	Propanil (DCPA mono- and di-acid degrad)
Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision:	Do Not List on 303(d) list (TMDL required list)(2016)
Revision Status	Original
Impairment from Pollutant or Pollution:	Pollutant

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the nine samples exceed the evaluation guidelines for aquatic life uses. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the nine samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 87554, Propanil (DCPA mono- and di-acid degrad)	Region 3
Watsonville Slough

LOE ID:

94188

Pollutant:

Propanil (DCPA mono- and di-acid degrad)

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for PROPANIL.

Data Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Propanil is the maximum acceptable toxicant concentration (MATC) of 0.5 ug/L.

Guideline Reference:

2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. California Department of Fish and Game, Monterey, CA

Spatial Representation:

Data for this line of evidence for Watsonville Slough was collected at 1 monitoring site [ 305WAT-Watsonville Slough below Beach Street Input - 305WAB]

Temporal Representation:

Data was collected over the time period 1/7/2008-10/28/2009.

Environmental Conditions:

QAPP Information:

USGS QAPP

QAPP Information Reference(s):


DECISION ID	68928	Region 3
Watsonville Slough

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

Regional Board Conclusion:	No new data are assessed. The decision has not changed .

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

State Board Review of Regional Board Conclusion and Recommendation:

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

Line of Evidence (LOE) for Decision ID 68928, Sedimentation/Siltation	Region 3
Watsonville Slough

LOE ID:

1856

Pollutant:

Sedimentation/Siltation

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

338

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Sediment concentration has been studied by many investigators. All available data was reviewed and summarized by (Hager, J. and F. Watson 2005).

For suspended sediment concentration, 338 representative measurements are available. None of the measurements exceed the sediment threshold.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect surface waters.

Objective/Criterion Reference:

Evaluation Guideline:

Three spine stickleback occurs in the Slough and in studies no mortality was observed in a test to identify the lethal threshold for sediment at a concentration of 28,000 mg/L (LeGore and Des Voigne, 1973).

Guideline Reference:

Spatial Representation:

Samples were collected at least 13 stations throughout the slough system.

Temporal Representation:

Samples were collected between 1976 and 2004 during all seasons.

Environmental Conditions:

QAPP Information:

Most of the data were collected under a Quality Assurance Project Plan prepared by Central Coast Watershed Studies, The Watershed Institute at California State University Monterey Bay.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 68928, Sedimentation/Siltation	Region 3
Watsonville Slough

LOE ID:

1854

Pollutant:

Sedimentation/Siltation

LOE Subgroup:

Narrative Description Data

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Smothering of benthic habitat by sedimentation was not significantly evident, but was also difficult to study. A visual reconnaissance was conducted for signs of excessive recent sedimentation. Unequivocal smothering of habitat could only be documented photographically in small portions of the Watsonville Slough system. Other areas were either stable, contained coarse sediment, contained fine sediment in amounts that did not contradict the expectation of a natural system, were under water, or were not accessible (Hager, J. and F. Watson 2005).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect surface waters.

Objective/Criterion Reference:

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

Most of the data were collected under a Quality Assurance Project Plan prepared by Central Coast Watershed Studies, The Watershed Institute at California State University Monterey Bay.

QAPP Information Reference(s):

Line of Evidence (LOE) for Decision ID 68928, Sedimentation/Siltation	Region 3
Watsonville Slough

LOE ID:

1855

Pollutant:

Sedimentation/Siltation

LOE Subgroup:

Narrative Description Data

Matrix:

Not Specified

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

Not Specified

Data Used to Assess Water Quality:

Long-term aggregation of sediments and reduction in aquatic habitat volume was not evident. Aquatic habitat volume appears to be increasing due to land subsidence associated with de-watering of the area for peat mining and agriculture in the early 1900s, ground water pumping, and possibly local seismic activity. Scientists re-surveyed an old road survey across Struve Slough and Watsonville Slough, and found evidence of subsidence on the order of 10 to 20 mm/year since 1952. Obtained sediment cores in the tidal marsh of lower Watsonville Slough dating back to the 1400s and they were analyzed using radiocarbon dating, pollen, and lead-210. The data suggested an anthropogenic increase in sedimentation surrounding the expansion of agriculture in the first half of the 1900s, but net sedimentation rates since about 1950 appear to have been lower than in pre-historic times. This is likely attributed to decreased sediment supply to the lower reaches resulting from subsidence and the construction of the tide gates in the 1940s (Hager, J. and F. Watson 2005).

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Basin Plan: The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect surface waters.

Objective/Criterion Reference:

Data for various pollutants in the Pajaro, Salinas, and Santa Maria River estuaries, Jan. 2008-Oct. 2009

Evaluation Guideline:

Guideline Reference:

Spatial Representation:

Temporal Representation:

Environmental Conditions:

QAPP Information:

Most of the data were collected under a Quality Assurance Project Plan prepared by Central Coast Watershed Studies, The Watershed Institute at California State University Monterey Bay.

QAPP Information Reference(s):


DECISION ID	87606	Region 3
Watsonville Slough

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

Regional Board Conclusion:	This pollutant is being considered for placement on the CWA section 303(d) List under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero of the nine samples exceed the evaluation guidelines for the protection of aquatic life beneficial use. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 16 samples is needed to determine if a beneficial use is supported and a minimum of two exceedances is needed to determine if beneficial uses are not supported using table 3.1. Therefore, the use support rating is set to 'insufficient information'. 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. Zero of the nine samples exceed the evaluation guidelines 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. 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 this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.

Line of Evidence (LOE) for Decision ID 87606, Thiobencarb/Bolero	Region 3
Watsonville Slough

LOE ID:

94192

Pollutant:

Thiobencarb/Bolero

LOE Subgroup:

Pollutant-Water

Matrix:

Water

Fraction:

None

Beneficial Use:

Warm Freshwater Habitat

Number of Samples:

Number of Exceedances:

Data and Information Type:

PHYSICAL/CHEMICAL MONITORING

Data Used to Assess Water Quality:

State Water Board staff assessed USGS data for Watsonville Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for THIOBENCARB.

Data Reference:

SWAMP Data:

Non-SWAMP

Water Quality Objective/Criterion:

Water Quality Control Plan for the Central Coastal Basin (CCRWQCB 2011): All waters shall be maintained free of toxic substances in concentrations which are toxic to, or which produce detrimental physiological responses in, human, plant, animal, or aquatic life. No individual pesticide or combination of pesticides shall reach concentrations that adversely affect beneficial uses. (Chapter III, Section II.A.2 Objectives for all Inland and Surface Waters, Enclosed Bays and Estuaries).

Objective/Criterion Reference:

Water Quality Control Plan for the Central Coastal Basin

Evaluation Guideline:

The evaluation guideline for Thiobencarb is the maximum acceptable toxicant concentration (MATC) of 1.4 ug/L.

Guideline Reference: